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Cai, Jie. "Hydropower in China." Thesis, University of Gävle, University of Gävle, Department of Technology and Built Environment, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-5839.
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Tchuidjang, Tchouaha Sebastien. "Hydropower in Cameroon." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-11304.
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Parmee, Ian Christopher. "Pneumatic hydropower systems." Thesis, University of Plymouth, 1990. http://hdl.handle.net/10026.1/2402.
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The following thesis investigates the performance and economics of a Pneumatic Water Engine capable of extracting energy from differential heads of water in the two to three metre range. Initial concepts are discussed and a system configuration is physically modelled at a laboratory scale. Outline designs using a variety of materials are developed and these provide a basis for the estimation of a probable capital cost using standard Civil Engineering methods. The proposed system is mathematically modelled using a lumped mass approach to the complex hydrodynamics. The resultant differential equations are solved by means of a variable Runge Kutta numerical analysis. The model includes the thermodynamic aspects of the system's compressible airflow. A computer program has been developed from the mathematical model and Is utilized in a series of parametric studies. An economic assessment based upon both the average power output achieved during the parametric studies and the probable capital cost of the system is presented, together with an estimate of the cost per kilowatt-hour of the electricity produced. This assessment takes into account maintenance costs, expected value of the energy produced and the possible effects of both Water Abstraction Charges and Local Authority Rating. In addition to the parametric studies a final, more rigorous optimization of the system involving a number of the many interacting variables has been undertaken. This optimization is achieved via Cumulative Evolutionary Design techniques involving the use of Genetic Algorithms. An optimal design of the chamber shape is achieved in the same manner.
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Malmquist, Peter, and Mats Sigfridsson. "The Kamchay Hydropower Project -Hydropower development in Cambodia and eastern Asia." Thesis, Malmö högskola, Fakulteten för teknik och samhälle (TS), 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20993.
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The objective in this case study is to highlight typical problems of a planned hydropower dam project in Bokor National Park, Cambodia. The focal point in the line of questioning is the usage of public participation in larger exploration plans in a development country and to give a comprehensive survey of some of the participant involved. The study also discusses how the WCD report is used by non-govemental organisation to validate their claims. To be able to understand how the Cambodian society works, the study also includes a short briefing of recent Cambodian history. The study shows that the local people are more or less neglected in the preliminary investigations. Even if information meetings are held open, they are conducted in such a way that it is hard for common people to participate. The meetings are held in English and not in the domestic language Khmer. Critical groups are not formally invited but welcome to attend, most of their statements are withdrawn from the official protocols. The study also reveals that the leading entrepreneurs more or less neglects the environmental hazards in the construction by focus their information and calculations on the positive effects of the project. The study has been made as a field study, on location in Cambodia.
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Duncan, Niall James. "Mapping Scotland's hydropower resource." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9664.
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Increased renewable electricity generation is key to the reduction of carbon emissions and has the added benefit of reducing reliance on imported gas and coal while increasing diversity of the generation mix. To encourage development of renewable generation the Scottish Government has adopted an ambitious 100% renewable electricity generation target to be met by 2020. Although hydropower has generally been considered insignificant in a UK context, when forming part of a Scottish target the resource becomes much more significant as the majority of the UK’s existing capacity and potential for new capacity is located within Scotland. Scotland has a long history of hydropower development with the majority of current operational capacity installed during the mid 20th century. Recent studies have produced a range of estimates for the remaining resource from 286 to 1000 MW. The studies undertaken have tended to rely upon catchment analogue methods or the use of regression equations to produce estimates of flow at sites of interest, with simple assumptions of installation costs and energy yield. This work uses a novel method combining time series flow data produced from a distributed hydrological model with GIS techniques and a detailed parametric cost model to enable a state-of-the-art hydropower resource model to be developed. The use of time series flow data allowed investigation of the spatial and temporal characteristics of the resource to be made, both run-of-river and impoundment schemes to be investigated and a preliminary assessment of the impact of climate change to be performed. Three financial scenarios have been considered using 5%, 10% and 15% discount rates as this is the most sensitive variable when assessing the feasibility of hydropower projects, reflecting the cost of finance available and investors’ attitude to risk. The spread of discount rates will account for changes in available subsidies, electricity prices and ongoing costs. Clearly availability of low cost finance and a low risk subsidy environment will have the largest impact on hydropower development. A major limiting factor was found to be the cost of grid connection; if this were reduced the potential figure could be higher. The results of this work show that at a 10% discount rate, 440 MW of new run-of river hydropower potential capable of producing 1.7 TWh per year is available. Exploitation of this would represent an additional 4% contribution towards the Scottish Government’s 100% renewable electricity target.
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Svensson, Marcial Alexander. "Optimal planning of hydropower." Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-96652.
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We are currently witnessing a rapid expansion of renewable power production, an increase dominated by wind and solar power. These intermittent energy sources, while having low production costs, increases the uncertainty on the electrical markets. Hydropower is a renewable source of electricity that is capable of controlled production. It is assumed that hydropower will take a more central role in terms of balancing deficiencies caused by intermittent sources. In this thesis, we present a detailed model of a single hydropower plant consisting of 𝑛 turbines. This model is then used as input of solving the optimisation problem of revenue maximisation for the hydro plant owner. The model used takes into account head effects as well as stochastic inflow of water and the stochastic fluctuations of electricity prices.
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Claesson, Jakob, and Sam Molavi. "Intelligent hydropower : Making hydropower more efficient by utilizing machine learning for inflow forecasting." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279609.
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Inflow forecasting is important when planning the use of water in a hydropower plant. The process of making forecasts is characterized by using knowledge from previous events and occurrences to make predictions about the future. Traditionally, inflow is predicted using hydrological models. The model developed by the Hydrologiska Byråns Vattenbalansavdelning (HBV model) is one of the most widely used hydrological models around the world. Machine learning is emerging as a potential alternative to the current HBV models but needs to be evaluated. This thesis investigates machine learning for inflow forecasting as a mixed qualitative and quantitative case study. Interviews with experts in various backgrounds within hydropower illustrated the key issues and opportunities for inflow forecasting accuracy and laid the foundation for the machine learning model created. The thesis found that the noise in the realised inflow data was one of the main factors which affected the quality of the machine learning inflow forecasts. Other notable factors were the precipitation data from the three closest weather stations. The interviews suggested that the noise in the realised inflow data could be due to faulty measurements. The interviews also provided examples of additional data such as snow quantity measurements and ground moisture levels which could be included in a machine learning model to improve inflow forecast performance. One proposed application for the machine learning model was as a complementary tool to the current HBV model to assist in making manual adjustments to the forecasts when considered necessary. The machine learning model achieved an average Mean Absolute Error (MAE) of 1.39 compared to 1.73 for a baseline forecast for inflow to the Lake Kymmen river system 1-7 days ahead over the period 2015-2019. For inflow to the Lake Kymmen river system 8-14 days ahead the machine learning model achieved an average MAE of 1.68 compared to 2.45 for a baseline forecast. The current HBV model in place had a lower average MAE than the machine learning model over the available comparison period of January 2018.<br>Tillrinningsprognostisering är viktig vid planeringen av vattenanvändningen i ett vattenkraftverk. Prognostiseringsprocessen går ut på att använda tidigare kunskap för att kunna göra prediktioner om framtiden. Traditionellt sett har tillrinningsprognostisering gjorts med hjälp av hydrologiska modeller. Hydrologiska Byråns Vattenbalansavdelning-modellen (HBV-modellen) är en av de mest använda hydrologiska modellerna och används världen över. Maskininlärning växer för tillfället fram som ett potentiellt alternativ till de nuvarande HBV-modellerna men behöver utvärderas. Det här examensarbetet använder en blandad kvalitativ och kvantitativ metod för att utforska maskininlärning för tillrinningsprognostisering i en fallstudie. Intervjuer med experter med olika bakgrund inom vattenkraft påtalade nyckelfrågor och möjligheter för precisering av tillrinningsprognostisering och lade grunden för den maskininlärningsmodell som skapades. Den här studien fann att brus i realiserade tillrinningsdata var en av huvudfaktorerna som påverkade kvaliteten i tillrinningsprognoserna av maskininlärningsmodellen. Andra nämnvärda faktorer var nederbördsdata från de tre närmaste väderstationerna. Intervjuerna antydde att bruset i realiserade tillrinningsdatana kan bero på felaktiga mätvärden. Intervjuerna bidrog också med exempel på ytterligare data som kan inkluderas i en maskininlärningsmodell för att förbättra tillrinningsprognoserna, såsom mätningar av snömängd och markvattennivåer. En föreslagen användning för maskininlärningsmodellen var som ett kompletterande verktyg till den nuvarande HBV-modellen för att underlätta manuella justeringar av prognoserna när det bedöms nödvändigt. Maskininlärningsmodellen åstadkom ett genomsnittligt Mean Absolute Error (MAE) på 1,39 jämfört med 1,73 för en referensprognos för tillrinningen till Kymmens sjösystem 1–7 dagar fram i tiden under perioden 2015–2019. För tillrinningen till Kymmens sjösystem 8–14 dagar fram i tiden åstadkom maskininlärningsmodellen ett genomsnittligt MAE på 1,68 jämfört med 2,45 för en referensprognos. Den nuvarande HBV-modellen hade ett lägre genomsnittligt MAE jämfört med maskininlärningsmodellen under den tillgängliga jämförelseperioden januari 2018.
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Kjærås, Halvor. "Sediments in Angostura Hydropower Reservoir." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for vann- og miljøteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19298.
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Reservoirs in areas with a high sediment yield will without mitigation sooner or later be filled up with sediments, reducing the volume available for regulation for electric generation. Flushing of sediments is a management strategy used in many reservoirs in the world, with varying degree of success. The Angostura reservoir is a shallow reservoir located on an inundated river, making it extra vulnerable to sedimentation. It is estimated a yearly inflow of 1.5 million tons of sediment. Other reservoirs are located upstream, and the flushing of these leads to large quantities of sediment inflow in a short period of time. In September every year, the water level in Angostura is partially drawn down to route this sediment through the reservoir. In November, the water level is drawn down completely, and a full sediment flushing is performed. The RESCON model is a spreadsheet program designed to find a technically feasible sediment management strategy that maximizes the economical benefits of the project. Flushing is modeled with a simple algebraic model. SSIIM is a three-dimensional computational fluid dynamics program designed for hydraulic engineering. Sediment erosion, transport and sedimentation can be modeled in a complex reservoir geometry using an adaptive grid with a moveable bed. The main objective of this thesis is to test the performance of the RESCON and SSIIM models. The RESCON model was tested on the November flushing to see if it can reproduce the measured volume of flushed sediments. SSIIM was used for simulation of sediment concentration distribution in the reservoir, and to model the September flushing. The results are compared to measured values. The reservoir geometry is based on bathymetry data from September 2011. Inflow series are from logged values at the hydropower plant. Depth-averaged concentration values are used to present the longitudinal concentration distribution, and Hunter Rouse profiles to present the vertical distribution. Using known reservoir values and the recommended coefficients, the RESCON model was not able to get close to the actual volume of flushed sediments. Although the model has given promising results in other cases, the complex reservoir geometry in Angostura sets heavy restrictions on the flushing processes in the reservoir, which an algebraic model of this type cannot reproduce. The steady state simulation was successful in explaining previously unexplained variations in the concentration in the lateral and longitudinal direction of the reservoir. The simulation reproduces the longitudinal and vertical concentration distribution well. A bug in the implementation of the second-order scheme in SSIIM was discovered, which has later been fixed, giving more similar results for the first-order and second-order schemes. The time allocated for the flushing simulation was not enough to get satisfactory results. The erosion in the upstream end is modelled well, but the measured sedimentation in the downstream area is much larger than in the simulations. With more time for this simulation, it would have been possible to increase the quality of the results.
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McMahon, George F. "The marginalization of federal hydropower." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/20197.
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Dogmus, Özge Can. "The "on-paper" hydropower boom." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21429.
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Der weltweite Wasserkraftboom wird entweder mit seinen Vorteilen (Hochwasserschutz, Wirtschaftswachstum, erneuerbare Energieerzeugung) oder negativen Auswirkungen betrachtet (Zerstörung intakter Lebensräume, Verdrängung der Bevölkerung und Bedrohung von
Existenzgrundlagen). Die vorliegende Arbeit versucht den Wasserkraftboom besser zu verstehen wie auch den Fakt, dass dieser bislang nicht zum Bau großer Wasserkraftwerke geführt hat. Eine
Fallstudie wurde von Juli bis Oktober 2016 und Juli bis August 2017 in Bosnien und Herzegowina durchgeführt.
Auch dort ist die Zahl der gebauten Wasserkraftprojekte im Vergleich zur Zahl der geplanten Projekte vernachlässigbar gering. Qualitative Forschungsmethoden wurden angewendet und drei wesentliche Schlussfolgerungen gezogen. Erstens (Kap. II) wird erläutert, warum der Boom in Bosnien und Herzegowina nicht in dem vorgesehenen Ausmaß stattfinden wird und inwieweit das Phänomen einer Übertragung auf globalen Maßstab standhält. Zweitens (Kap. III) wird deutlich, wie v.a. kleinere Wasserkraftprojekte von Akteuren zum persönlichen Vorteil genutzt werden. Korruption ist in diesem Sektor weit verbreitet und eng mit dem Diskurs über nachhaltige Entwicklung im Land verbunden. Die kleinen Wasserkraftprojekte schaffen einen sicheren Raum für korrupte Akteure. Schließlich (Kap. IV) wurde untersucht, wie die BewohnerInnen eines kleinen Dorfes in Bosnien und Herzegowina ihre Vorstellungen von Nachhaltigkeit rund um die Wasserkraft verändert haben. Dies taten sie in Übereinstimmung mit sich ändernden sozioökonomischen Bedingungen. Dieses Kapitel illustriert, wie die Flexibilität des Begriffs Nachhaltigkeit für marginalisierte lokale BewohnerInnen von Vorteil sein kann. Die vorliegende Dissertation zeigt, dass der Wasserkraftboom, obwohl bislang weitgehend nur "auf dem Papier" existent, dennoch bereits reale materielle Konsequenzen für nachhaltige Entwicklungsstrategien, Korruption und das lokale Leben mit sich bringt.<br>The global hydropower boom is a well-known phenomenon. It is either considered for its benefits to sustainable development or cautioned against its negative socio-environmental impacts. Yet the number of existing hydropower projects is not very high globally. This thesis thus aspires to develop a better understanding of the global hydropower boom and why this boom has not resulted in large-scale hydropower plant construction. The hydropower boom in Bosnia and Herzegovina was selected as the object of study. There, the number of constructed hydropower projects is negligible in comparison to the number of planned projects. Qualitative research methods were used to explore the case in depth. The data was collected between July and October, 2016 and between July and August, 2017.
Three main conclusions were drawn from the fieldwork conducted. Chapter II shows and explains why the hydropower boom is unlikely to take place in Bosnia and Herzegovina to the extent foreseen. It also questions the phenomenon at a global scale. Chapter III shows how small-scale hydropower projects are used by various actors for personal benefit. Corruption is rife in the sector and closely connected to the sustainable development discourse in the country. A key finding here is that small-scale hydropower projects create a safe space for corrupt actors. Chapter IV explores how the inhabitants of a small village in Bosnia and Herzegovina changed their sustainability imaginaries around hydropower. They did this in accordance with changing socio-economic conditions. This chapter thus illustrates how the flexibility of the term sustainability can be beneficial to marginalised local inhabitants. In general, this thesis, therefore, contributes to the hydropower literature. It shows that the hydropower boom is largely ‘on-paper’ but with real material consequences for sustainable development strategies, corruption, and local lives.
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Wiebert, Julia, and Minna Sahlsten. "The Untapped Potential of Hydropower." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217339.
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Karlberg, Anna. "Swedish hydropower : A literature study about Swedish hydropower, environmental impact and EU: s Water Framework Directive." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-20301.
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In Sweden, EU: s Water Framework Directive led to an investigation that started in April 2012 by the Swedish government, called Vattenverksamhetsutredningen freely translated to "Water Activities Survey", with the purpose to investigate the Environmental Code’s rules concerning water activities and water plants. The survey is divided into 3 reports, two sub-reports and a final report. One of the sub-report is focused on Swedish hydropower and the investigators found that many hydropower plants have old permits. One suggestion in the survey was to reconsider old permits so they would become consistence with today’s Environmental Code. There have been discussions regarding whether Sweden will lose much of its electricity production from hydropower as an outcome if the survey’s suggestions becomes reality. The aim with this literature study is to investigate how the EU: s Water Framework Directive and the Water Activities Survey will affect Swedish hydropower and if there will be a decrease in electricity production as an outcome if the suggestions made in the survey becomes reality. The results in this literature study shows that there will probably be a decrease in production for Swedish hydropower, but with how much is hard to say because the Swedish government has not yet decided what they will do with the suggested actions in the Water Activities Survey. A comparison is done with Sweden’s import and export statistics between the years 2001-2014 with a predicted loss of 13 TWh per year, which is a number taken from a survey made by Vattenfall. A comparison with a loss of half of 13 TWh per year is also done. Between the years 2001 and 2014 Sweden imported electricity 6 out of 14 years and exported electricity 8 out of 14 years. If adding the predicted loss of 13 TWh per year to the import and export statistics, Sweden would have had to import electricity 12 years and export 2 years. If adding a loss of 6.5 TWh per year Sweden would have had to import electricity 8 years and export 6 years. The conclusions is that Sweden will have to import a lot more electricity if only looking at import and export statistic if the loss of electricity is between 6.5-13 TWh per year.
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Mashkour, Mohammad. "Micro hydropower in water distribution systems." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17855/.
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Considering various applications of Pump as Turbine (PAT) as an effective source of reducing the
equipment cost in small hydropower plants as well as the selecting process of appropriate location
and suitable machinery are the main concerns of this study. Vary range of PAT settings criteria
has been propound by taking into account the State-of-the-Art researches.
The purpose of this study is to establish the effectiveness of pump as turbine, considering all the
possible obstacles such as producer’s market interests, accessibility of technical information and
mechanical limitation. Cutting-edge scientific researches concerning PAT have been proposed by
implementation of various approaches. The most challenging criteria of PAT, which is selecting
the appropriate machinery, has been investigated subsequently.
A comparative methodology to model the effectiveness of PATs, both numerical and experimental,
has been developed based on the efficiency. The mechanical reliability of the hydropower devices
in situ, prototype and numerical investigation have been reviewed. These results have been
obtained through measurements and optimization of the simulated system by means of
characteristic methods against the established PAT system in many different case studies.
Water Distribution Networks (WDNs) allow to obtain a widespread and globally significant
amount of produced energy by exploiting the head drop due to the network pressure control
strategy for leak reductions. Replacing PAT in water distribution networks regarding to all the
possible obstacles, will reduce the final cost and will improve the expected efficiencies, as much
as the reduction of environmental impacts.
This study definitively answers the question whether PAT is an effective alternative in WDNs.
The comparative approach also aims for a better understanding of the impact of PAT on the
transition to renewable energy systems.
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Crona, Mats. "Evaluation of flexibility in hydropower stations." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-167674.
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This report seeks to evaluate the flexibility in a number of Fortum’s hydropower stations. The deregulation of the Nordic electricity market has put an emphasis on revenue maximizing rather than cost minimizing and there are good indications that flexible assets will be even more valuable in the future when more wind power has been introduced into the system. Through interviews with people involved in the hydropower planning and operation process a number of factors with the potential of affecting the flexibility or causing deviations between planned and realized operation have been identified and explained. These interviews have also been used to identify main flexibility limitations in studied stations, and what potentially could be done to improve the flexibility. A data analysis has been performed where historical data from planned and realized operation and results from a model developed in Matlab has been studied. The developed linear programming model is used as a reference level of an idealized theoretical potential for flexibility. Volume weighted average prices have been used to measure and compare the flexibility of studied stations. The analysis shows that the studied stations can be divided into two groups with regards to their flexibility compared to the modeled flexibility. This result is somewhat confirmed by the interview findings. Factors related to constraints imposed by water rights seem to have the biggest single impact on the flexibility of hydropower stations. The potential for flexible operation varies with season and the planned and realized operation is closer to the modeled results during the winter. It is a general opinion within the organization that there is a potential for a more flexible utilization of many hydropower stations. Experience, resources, understanding in how to fully utilize the reservoirs, and how multiple stations in a river reach can be coordinated are keys to improving the flexibility.
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Bladh, Johan. "Hydropower generator and power system interaction." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-182188.
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After decades of routine operation, the hydropower industry faces new challenges. Large-scale integration of other renewable sources of generation in the power system accentuates the role of hydropower as a regulating resource. At the same time, an extensive reinvestment programme has commenced where many old components and apparatus are being refurbished or replaced. Introduction of new technical solutions in existing power plants requires good systems knowledge and careful consideration. Important tools for research, development and analysis are suitable mathematical models, numerical simulation methods and laboratory equipment. This doctoral thesis is devoted to studies of the electromechanical interaction between hydropower units and the power system. The work encompasses development of mathematical models, empirical methods for system identification, as well as numerical and experimental studies of hydropower generator and power system interaction. Two generator modelling approaches are explored: one based on electromagnetic field theory and the finite element method, and one based on equivalent electric circuits. The finite element model is adapted for single-machine infinite-bus simulations by the addition of a network equivalent, a mechanical equation and a voltage regulator. Transient simulations using both finite element and equivalent circuit models indicate that the finite element model typically overestimates the synchronising and damping properties of the machine. Identification of model parameters is performed both numerically and experimentally. A complete set of equivalent circuit parameters is identified through finite element simulation of standard empirical test methods. Another machine model is identified experimentally through frequency response analysis. An extension to the well-known standstill frequency response (SSFR) test is explored, which involves measurement and analysis of damper winding quantities. The test is found to produce models that are suitable for transient power system analysis. Both experimental and numerical studies show that low resistance of the damper winding interpole connections are vital to achieve high attenuation of rotor angle oscillations. Hydropower generator and power system interaction is also studied experimentally during a full-scale startup test of the Nordic power system, where multiple synchronised data acquisition devices are used for measurement of both electrical and mechanical quantities. Observation of a subsynchronous power oscillation leads to an investigation of the torsional stability of hydropower units. In accordance with previous studies, hydropower units are found to be mechanically resilient to subsynchronous power oscillations. However, like any other generating unit, they are dependent on sufficient electrical and mechanical damping. Two experimentally obtained hydraulic damping coefficients for a large Francis turbine runner are presented in the thesis.
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Nordtveit, Audun, and Kim Thomassen Watle. "Toward hedge ratios for hydropower production." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for industriell økonomi og teknologiledelse, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20913.
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The electricity price and production volume determine the revenue of a hydropower producer. Inflow variations to hydro reservoirs and high price volatility result in significant cash flow uncertainty. A copula-based Monte Carlo model is used to relate price and production volume, and to find optimal hedge ratios through minimization of risk measures such as variance, hedge effectiveness, cash flow at risk and conditional cash flow at risk. All risk measures argue for an optimal hedge ratio between 35 and 60\% of expected production. The highest risk reduction is achieved by the use of forward contracts with long time to maturity, but at the expense of a low risk premium. Conversely, short-term futures and forwards only provide marginal risk reduction, but can yield attractive positive risk premiums. These findings underline the importance of distinguishing the use of derivative contracts for speculation and hedging purposes, through positions in short-term and long-term contracts respectively.
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Braathen, Jørgen, and Anders Lund Eriksrud. "Hydropower Bidding Using Linear Decision Rules." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for industriell økonomi og teknologiledelse, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24844.
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This thesis investigates the Linear Decision Rule (LDR) approach applied to the bidding problem of a Nordic hydropower producer with reservoir capacity. A stochastic programming model with piecewise LDR in the spot prices is developed. A comprehensive case study with uncertain spot prices conducted for the fall of 2012 shows that the LDR model performs equally well as a scenario based model on expectation, yet with a smaller standard deviation in the profits. The runtime of the LDR model is substantially longer than the runtime of the scenario based model. Therefore, promising techniques to reduce the runtime are developed and presented.
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Karlsson, Irene. "Hydrological data for small hydropower plants." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for vann- og miljøteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26644.
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During last years extensive development of small hydropower plants has taken place, and many of that plants are frequently located in small catchments. Mainly there is no runoff data for these small catchments, because runoff gauging stations have been established in comparably larger catchments. For establishing runoff for small catchments it is common practice to downscale it from larger catchments – analogue catchments. For downscaling analogue stations should have nearly the same catchment characteristics, like area, lake percentage, elevation distribution, etc. Small hydropower catchments often don’t have lakes, it means that small catchments have faster runoff response and more “peaked” hydrographs, comparably to larger catchments. In this case scaling approach will lead to wrong design and disappointing results during operation. Underestimation of runoff data will lead to additional spill of water, and overestimation will bring to wrong installed capacity and may be would not be efficient at all. During past years consulting companies become very interested in more precise runoff data, even if it have been collected during not long time period. It has been decided to set a gauging stations near to projects and collect runoff data (even for short period). In the past 10 years SWECO AS company has collected runoff series for approximately hundred stations, which are located through all Norway. Collected runoff series are also very valuable for other hydrological computations, it could improve and adjunct NVE data for small catchment and supplement hydrological data where NVE has no stations. This study was made with permission of SWECO AS (Trondheim) and people who have paid for data collection.The objectives of the Thesis is to store all available runoff data to the database in proper format (using HEC-DSS programm), collect necessary information about each station and compute topographical and climatic parameters (using NVE Low-flow application), make a standardized description of each record (station) including all important information like location (GPS), map, photo, catchment characteristics, rating curve etc. and check the quality of data.In this project one of the objectives is to prepare runoff data series to transfer to NVE database in tidy and in the format that requested NVE.During Thesis work one of the objectives is to make an comparable analysis between SWECO stations data and NVE analogue stations. Data from NVE analogue stations was provided by NVE staff. Besides, relationship between topographical and climatic parameters with flow duration curves of selected SWECO stations should be estimated.
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Ölund, Martin. "Electrical Surge Protection at Hydropower Plants." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-310318.
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Hydropower plants contains a lot of vital electrical power technology such as generators and transformers. To prevent damage to this equipment due to overvoltage, they are often protected by surge arrester and in some cases also by surge capacitors. The design and dimension of these components vary between different sites and regions and are often done using a template without considering the actual conditions of the site. In this thesis Simulink and Simscape Power System are used to study the case when a hydropower station is exposed to overvoltage. One of Fortum’s hydropower stations is simulated when being exposed to lightning and switching overvoltage to see how the existing overvoltage protection handles this stress. The results show that the surge arresters mounted in front of the generator managed to keep it safe for all overvoltage scenarios it is exposed to. They also shows that the surge capacitors mounted in front of the generator reduces the gradient of the overvoltage surge. However, as the surge arresters already keeps the overvoltage at safe levels, there is no need of reducing the overvoltage gradient and the surge capacitors becomes excessive in this particular hydropower plant.<br>Vattenkraftverk innehåller många vitala komponenter så som generatorer och transformatorer. För att skydda dessa oftast väldigt dyra komponenter mot överspänningar, används ventilavledare och ibland också överspänningskondensatorer. Utformning och dimensionering av skydden varierar mellan olika anläggningar och regioner. Dimensioneringen av skydden görs ofta schablonmässigt, utan någon väsentlig anpassning till de faktiska förhållandena. I detta examensarbete används simuleringsverktyget Simulink tillsammans med tillägget Simscape Power Systems för att simulera vad som händer när ett vattenkraftverk utsätts för olika överspänningar. Ett av Fortums vattenkraftverk studeras när det utsätts för blixt- och kopplingsöverspänningar för att se vad ventilavledarna samt överspänningskondensatorerna i denna anläggning fyller för funktion. Resultaten visar att ventilavledarna monterade framför generatorn klarar av att hantera alla överspänningar de utsätt för under simuleringarna. Resultaten visade också att överspänningskondensatorerna monterade framför generatorn sänker spänningsgradienten, men eftersom ventilavledarna redan håller spänningen på en säker nivå blir överspänningskondensatorerna överflödiga i denna station.
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Hagman, Sarah, and Julia Lindberg. "CBA of environmental projects within hydropower." Thesis, KTH, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-246132.
Full textAbstract:
Hydropower is a fundamental pillar in the Swedish energy system and accounts for a large part of the Swedish electricity production. The regulation power is also essential for balancing the grid load. Fortum is one of the leading energy companies within hydropower and Klarälven is a river with high importance, where Fortum owns and operates nine powerplants. These power plants constitute a barrier for the wild salmonids in Klarälven, which need to migrate upstream to reach their spawning area. Since the 1930s, the spawning salmonids have been trapped and transported upstream by lorry. After the spawning period, the smolts and kelts, i.e. the juvenile and spawned salmonids, have to migrate downstream. Due to the lack of fishways, they are forced to pass the eight remaining power plants. This, together with predation, entails a high mortality rate. Two independently performed studies indicates on survival rates of 16 % and 30 %. To stabilize the wild salmonid population, the downstream survival must increase, and a proposed solution is to implement a downstream trap-and-transport solution. This trap implementation could be a step towards the environmental adaptation of hydropower and a part of the action plan proposed in June 2016, during the Agreement on Swedish energy policy. To find the most cost-beneficial environmental measure, a socio-economic assessment method can be used. A Cost-Benefit Analysis (CBA) is a commonly used socio-economic method, which evaluates the benefits and costs during the entire project lifetime. Energiforsk has, within the project FRAM-KLIV, developed a CBA tool that aims to simplify the socio-economic evaluation. The purpose of this thesis was to investigate whether the CBA tool can be used in future permit processes to prioritize between different project proposals to find the most beneficial environmental improvements. In order to evaluate the tool, it was to be applied on the trap-and-transport project in Edsforsen to evaluate the possibility of a socio-economic profitability. Also, the concepts and theory behind CBA was to be analysed and the suitability of translating environmental consequences into monetary values was to be evaluated. In the analysis of Edsforsen, 13 scenarios were developed. The first scenario served as a basis for the other scenarios, which were created as a sensitivity analysis. The result of the CBA showed a large socio-economic benefit and the most important parameter was identified as people’s willingness to pay for an increase of the wild salmonid stock in Klarälven. In the CBA, this parameter had a high uncertainty, as it was based on a survey performed for another project in another part of Sweden. It was found that in order for the socio-economic result to be positive, all households in Sweden must be willing to pay at least 35 SEK. As a complement to the CBA result, an evaluation regarding the marginal cost per fish was performed and an interval of 50-580 SEK per smolt was obtained. However, the calculations were based on several uncertainties and the interval should therefore be interpreted as a guideline rather than a precise result. It was concluded that in situations when a socio-economic analysis is required, and when it is possible to express consequences in monetary values, the method of CBA is appropriate. It is also a suitable methodology for evaluations of large projects, as it provides a comprehensible overview of the costs and the benefits. Despite the criticism directed towards CBA regarding uncertainties and its anthropogenic perspective, it could be concluded that using CBA as a socio-economic assessment method provides a perspicuous and quantitative result. Thus, the usage of CBA in prioritization processes of different environmental measures can be highly useful. Energiforsk’s CBA tool provides a framework with guidelines that can be highly useful and accelerate the analysis process. However, the performance of the tool version used in this thesis was not fully satisfactory due to a few malfunctions. The tool is still under development and it is likely that these errors will be adjusted in future versions. If the malfunctions in the tool would be adjusted, it could become useful for authorities, companies and other actors that wants to evaluate hydropower related environmental measures or when prioritizing between different project proposals to find the most beneficial environmental improvements in future permit processes.<br>Vattenkraften är en grundläggande pelare i det svenska energisystemet och står för en stor andel av den svenska elproduktionen på årsbasis. Vattenkraften har även hög betydelse för det svenska nätets balanseringsförmåga. Fortum är ett av de ledande energibolagen inom vattenkraft i Sverige och en viktig älv för dess kraftproduktion är Klarälven. Denna älv är dessutom fundamental för Klarälvslaxen och Klarälvsöringen och dess nödvändiga lekvandring. Under naturliga förhållanden ska den lekmogna laxen vandra uppströms Klarälven, men denna vandring försvåras av vattenkraftverken. Sedan 1930-talet har laxen transporterats uppströms Klarälven med lastbil för att nå sina lekområden, men när smolten och kelten ska vandra nedåt för att nå Vänern på nytt måste den passera de resterande åtta vattenkraftverken, vilket tillsammans med predation resulterar i en hög dödlighet. Två oberoende studier indikerar en överlevnad på 16 % respektive 30 %. För att stabilisera det vilda laxbeståndet föreslås en uppfångsanordning med nedströmstransport, där fisken fångas upp i en fälla och transporteras nedströms med lastbil. I juni 2016 beslutades det genom Energiöverenskommelsen att vattenkraften ska miljöanpassas och ett genomförande av en sådan fälla skulle möjligen kunna vara en sådan miljöanpassning. För att finna de mest lönsamma miljöanpassningarna inom vattenkraften bör samhällsekonomiska lönsamhetsbedömningar genomföras. En kostnadsnyttoanalys (CBA) är sådan bedömningsmetod där kostnader och nyttor genererade under projektets livstid ställs mot varandra. Genom projektet FRAM-KLIV har Energiforsk varit med och tagit fram ett CBA-verktyg som ska underlätta genomförandet av en sådan beräkningsanalys. CBA-verktyget användes som ram i det här examensarbetet där en kostnadsnyttoanalys gällande laxens förbättrade nedströmspassage genomfördes och utvärderades. Syftet med detta examensarbete har varit att undersöka huruvida detta CBA-verktyg skulle kunna användas i framtida prioriteringar under tillståndsprocesser för att hitta de mest lönsamma miljöanpassningarna. Dessutom skulle bakomliggande koncept och teori analyseras. Tillika skulle en utvärdering gällande lämpligheten i att värdera miljövärden i monetära termer utföras. I arbetet utformades totalt tretton scenarier, varav det första ansågs som grundscenariot och utgjorde basen för de övriga tolv, vilka skapades för att identifiera de mest kritiska parametrarna genom en känslighetsanalys. Kostnadsnyttoanalysens erhållna resultat tydde på en stor samhällsekonomisk lönsamhet och den mest kritiska parametern identifierades som människors betalningsvilja för en ökad vildlaxpopulation i Klarälven. Osäkerheten kring denna parameter var stor då den baserats på en annan projektundersökning i en annan del av landet. För att erhålla ett positivt samhällsekonomiskt resultat visade denna undersökning att det måste finnas en betalningsvilja på minst 35 kr per hushåll i Sverige. Som ett komplement till resultatet utfördes en beräkning gällande hur mycket varje smolt skulle behöva vara värd för att den samhällsekonomiska nyttan ska vara lika stor som kostnaden. Beräkningen gav ett intervall mellan 50 och 580 kr, men då använd data innehöll stora osäkerheter bör resultatet ses mer som en riktlinje och inte ett exakt resultat. En slutsats som kunde dras var att det anses lämpligt att uttrycka miljövärden i monetära värden när en samhällsekonomisk analys är nödvändig. CBA som metod anses också vara lämplig och användbar när större projekt ska analyseras eftersom den ger en bred bild över fördelningen mellan kostnader och nyttor. Metoden förser dessutom användaren med ett lättolkat och överskådligt resultat och därav skulle CBA som metod vara lämplig gällande prioritering av miljönyttor. Energiforsks CBA-verktyg kan underlätta processen i och med att det ger användaren en ram med riktlinjer för hur beräkningsprocessen ska gå till. Verktygsversionen som användes i detta examensarbete uppfyllde dock inte full tillfredsställelse vad gällde dess funktionalitet. Verktyget är visserligen fortfarande under utveckling och det är möjligt att dessa funktionsfel kommer att justeras i framtida versioner. Om dessa justeringar sker kan verktyget komma att bli fullt funktionsdugligt och vara användbart för myndigheter, företag och andra aktörer som vill utvärdera vattenkraftrelaterade miljöåtgärder eller som prioriteringsverktyg gällande miljöförbättringar inom framtida tillståndsprocesser.
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de, Faria Felipe Aguiar Marcondes. "Hydropower Development in the Brazilian Amazon." Research Showcase @ CMU, 2016. http://repository.cmu.edu/dissertations/830.
Full textAbstract:
Brazil plans to meet the majority of its growing electricity demand with new hydropower plants located in the Amazon basin. The government’s energy policy forecasts the construction of 55 GW of installed capacity by 2028, with total investments in the range of 100 and 200 billion reais (30 to 60 billion dollars), and the creation 9,000 km2 of artificial reservoirs. However, the construction and operation of large hydropower plants may affect the environment, the local economy, and the population surrounding those projects. Considering the magnitude of the investments and the potential impacts for the Amazon basin, it is crucial to apply policy analysis techniques to support informed decisions about whether the construction of large hydropower plants in the Amazon is the best alternative to supply the additional electricity that Brazil needs, taking into account economic, social, and environmental costs and benefits. Here, I apply three different quantitative policy analysis techniques to assess three major questions related to the construction of hydropower plants in the Amazon region. First, I study the greenhouse gas emissions from hydropower reservoirs in the Amazon. Second, I explore the local socio-economic impacts of building hydropower plants. Finally, I investigate alternative electricity sources that could replace Amazon hydropower reservoirs by modeling the Brazilian electricity network under five capacity expansion scenarios.
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Aase, Anne Guri. "A new approach towards comparing environmental impacts from small-scale hydropower, large-scale hydropower and wind power." Thesis, Norges teknisk-naturvitenskapelige universitet, Geografisk institutt, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22901.
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In 2012 did Norway, in collaboration with Sweden, agree on a common energy certificate market where both countries set a goal for producing 67, 5 TWh of renewable energy within the year 2020. These certificates are energy neutral, but they are expected to increase the building of small-scale hydropower and wind power plants. This has created much debate surround the environmental impacts and habitat fragmentations which occur from the increased building, and more knowledge is needed to establish better mitigation measures. This thesis is therefore built on the need for more knowledge of the impacts from Norway’s two largest renewable energy resources: hydropower and wind power. I have tried to make a new methodological approach for mapping environmental impacts from three production types: small-scale hydropower, large-scale hydropower, and wind power, based on the same amount of annually produced energy. The mapped impacts are from four parameters: area directly affected by the production site, the visibility of the plant, amount of red listed species present within a radius of 2 and 10 kilometers, and amount of overlap with encroachment-free (INON) areas mapped by the Directorate for nature management in 2008. This new methodological approach is based in the program geographic information systems (GIS) using data downloaded from the Norwegian Mapping Authority and Artsdatabanken. The four parameters which are analyzed in GIS explores how the impacts from the three different power production types differ, and if the results can be used for a comparison of environmental impacts across different types of energy production.
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Flood, Cecilia. "Hydropower in Sweden : An investigation of the implications of adding detail to the modelling of hydropower in OSeMOSYS." Thesis, KTH, Energisystemanalys, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-163415.
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The purpose of this thesis is to generate a deeper understanding of the representation of hydropower in long-term models. This is done by mapping and modelling (cascading) hydropower in Sweden with the Open Source energy MOdelling SYStem (OSeMOSYS). The first part of the thesis builds on a literature review and provides an introduction to hydropower in Sweden. The second part focuses on implementing the storage equations in OSeMOSYS. These are applied by modelling hydropower at various levels of detail to evaluate the result when the depth of detail of the storage modelling is increased. First, a model of Sweden without hydropower storage is modelled. Then, two models were set up which include storage; one with one hydropower storage for all of Sweden, one with nine rivers with storage. Finally, two models considering cascading hydropower with storage were developed; where the first is an expansion of the model with one storage for all of Sweden and the second model examine two rivers more thorough. The remain-ing power system is represented in a stylised fashion, compliant with prevailing long-term energy modelling techniques. The implications of the different levels of detail are compared and discussed. The comparisons show that it is important to consider the lev-el of detail when looking at the short-term effects of long-term energy models.
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Baskar, Ashish Guhan, and Araavind Sridhar. "Short Term Regulation in Hydropower Plants using Batteries : A case study of hydropower pants in lower Oreälven river." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-289407.
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Hydropower is one of the oldest renewable energy (RE) sources and constitutes a major share in the Swedish electricity mix. Though hydropower is renewable, there exist some issues pertaining to the local aquatic conditions. With more environmental laws being implemented, regulating the use and management of water is jeopardizing the flexibility of hydropower plants. The decided national plan for new environmental conditions in Sweden is expected to start being implemented in 2025 and more restrictions are expected. Analysing a battery energy storage system's capabilities plants may improve flexibility in hydropower plant operation. This thesis is focused on the short-term regulation in lower Oreälven river where the hydropower plants Skattungbyn, Unnån and Hansjö are located. The combined hydropower plant and battery system is simulated being employed in the day-ahead market and a techno-economic optimization of the combined system is performed. The combined system's operation is modelled using Mixed Integer Linear Programming. The future electricity market analysis is modelled using Machine Learning techniques. Three different electricity market scenarios were developed based on different Swedish nuclear energy targets for 2040 to capture the future. The first scenario developed complies with the Swedish energy target of 100 % renewable production in 2040. The second scenario has still two nuclear power plants in operation by 2040 and the third scenario has the same nuclear capacity as of 2020. It is observed from the results that with the current battery costs (~3,6 Million SEK/MWh), the implementation of a battery system for the short term regulation of the combined battery/hydropower system is not profitable and the cost of battery needs to be less than 0,5 Million SEK/MWh to make it profitable. The thesis also discusses the possibility of utilizing batteries’ second life and the techno-economic analysis of their performance.<br>Vattenkraft är en av de allra äldsta förnybara energikällorna och utgör idag en väsentlig del av Sveriges energimix. Trots att vattenkraft är förnybar, har den lett till vissa utmaningar i den lokala vattenmiljön. Som en följd av att fler miljölagar har implementerats för att reglera nyttjandet av vattendrag och sjöar, minskar flexibiliteten i vattenkraftproduktionen. Den av den svenska regeringen i juni 2020 beslutade nationella planen för miljöanpassning av vattenkraften i Sverige, förväntas börja genomföras med start 2025 och tros då resultera i fler flexibilitetsbegränsningar. Genom att analysera driften av batteriers energilagringssystem kombinerade med vattenkraftverk, bedöms flexibiliteten i sådana kombinerade system kunna ökas. Denna studie fokuserar på den kortsiktiga regleringen av nedre Oreälven med vattenkraftverken Skattungbyn, Unnån och Hansjö. En kombination av vattenkraftverken med batterisystem simuleras mot spot-marknaden och en teknisk-ekonomisk optimering av det kombinerade systemet utförs. Driften av det kombinerade systemet modelleras med linjärprogrammering och den framtida analysen av elmarknaden modelleras med maskininlärningstekniker. Tre olika scenarier för elmarknaden utvecklades baserade på målen för den svenska kärnkraften år 2040. Det första scenariot som utvecklades är i linje med det svenska energimålet om 100 % förnybar produktion till 2040. Det andra scenariot utvecklades med två kärnkraftverk fortfarande i drift 2040 och det tredje scenariot med samma kärnkraftskapacitet som 2020. Från resultaten kan särskilt noteras att med nuvarande batterikostnader (~3,6 miljoner SEK/MWh) kommer införandet av batterier för att kortsiktigt reglera vattenkraftverken inte att vara lönsamt om inte batterikostnaden reduceras till som högst 0,5 miljoner SEK/MWh. Denna studie diskuterar även möjligheterna att använda andrahandsbatterier samt en teknisk-ekonomisk analys för dess prestanda.
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Vistica, Marko. "Value of stochasticity in hydropower planning optimization." Thesis, KTH, Elektriska energisystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103184.
Full textAbstract:
With respect to market liberalization, efficient use of resources is becoming more important for players in the market. In order to achieve that different optimization techniques were developed which enable better operational efficiency. These techniques can be segmented in to two different categories, depending on their time horizon: • Yearly time horizon – mid-term hydropower scheduling • Daily time horizon – short-term hydropower scheduling These two time horizons account for two case studies presented in this thesis. In the first case study (mid-term planning), the focus is on determining power plant’s optimal operating strategy, while taking into account the uncertainty in inflows and prices. Stochastic dynamic programming has been chosen as mid-term optimization technique. Since stochastic dynamic programming calls for a discretization of control and state variables, it may fall under the curse of dimensionality and therefore, the modeling of stochastic variables is important. By implementing a randomized search heuristic, a genetic algorithm, into the existing stochastic dynamic programming schema, the optimal way of using the stochasticity tries tobe found. Two price models are compared based on the economic quality of the result. The results give support to the idea of using search heuristics to determine the optimal stochasticity setup, however, some deviations from the expected results occur. Second case study deals with short-term hydropower planning, with a focus on satisfying the predefined demand schedule while obtaining maximum profit. With short-term hydropower planning being a nonlinear and nonconvex problem, the main focus is on the linearization ofunit performance curves, as well as satisfying technical constraints from the power plan tperspective. This optimization techniques also includes the water value in the solution. The problem has been solved by means of mixed integer linear programming. The results from the second case study are fully in line with the expectations and it is shown that mixed integer linear programming approach gives good results with good computational time. Suggested improvements to the model and potential for future work can be found in the final chapter of this thesis.
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Nielsen, Lars Eid, and Bjørnar Rettedal. "Different Aspects of Flushing of Hydropower Intakes." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for vann- og miljøteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18703.
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Different design criteria for successful flushing of hydropower headworks have been evaluated. Main focus has been on handling of floating debris for small hydropower plant in Norway, as well as sediment handling for run of the river-projects in sediment-carrying rivers. As a new way of cleaning intake screens clogged by debris, the concept of backflushing has been investigated. The intake screen, called trash rack, is then cleaned by a reveresed water flow over a short period of time, and the clogged material flushed out thorugh a flushing pipe. A physical test tank was developed to evaluate parameters for a successful flushing of trash racks with different degrees of clogging. A test device was developed to evaluate adhesion, i.e. the level of friction between clogged material and the trash rack. The required gross water velocity over a trash rack during flushing for detaching of the clogged material was found to be in the range of 0.1 to 0.2 m/s, with a typical value of 0.12 m/s. The clogged material tend to resist a maximum limit of pressure difference over the trash rack before it detaches. Results are showing a pressure difference resistance in the range of 0.05-0.10 meterWater Column (mWC). The pressure difference prove hard to obtain as parts of the trashrack is cleaned. Hence, a flushing gate should be opened at a high rate to obtain the best flushing efficiency.A field trip to Nepal has been conducted to gain experience in sediment handling, and to work with physical models at HydroLab Pvt Ltd in Kathmandu. Observed intake solutions have been evaluated both against existing theory and results from a physical model study. It has been documented through a model test series that the flushing ability of an undersluice gate is limited to only a few meters upstream of the flushing gate.The limit for flushing by bed transport has been tested in a model, and compared to theory for evaluating initial movement of the sediment bed. Experiments are supporting that Shield’s theory of critical shear stress can be used to predict the occurrence of bed movement. Design and operation of settling basins have been investigated, together with the appurtenant different strategies for flushing. The possibility of applying the concept of backflushing of trash racks for headworks arrangements including sediment settling basins have been evaluated. For projects where the trash rack can be located upstream of the settling basin, the combination seems feasible, as parts of the water storage in the settling basin could be used for the backflushing. However, the trash rack should be placed downstream of the settling basins for most Himalayan headworks arrangements, which makes backflushing impossible.
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Marko, Vistica. "Value of Stochasticity in Hydropower Planning Optimization." Thesis, KTH, Elektriska energisystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101702.
Full textAbstract:
With respect to market liberalization, efficient use of resources is becoming more important for players in the market. In order to achieve that different optimization techniques were developed which enable better operational efficiency. These techniques can be segmented into two different categories, depending on their time horizon: • Yearly time horizon – mid-term hydropower scheduling • Daily time horizon – short-term hydropower scheduling These two time horizons account for two case studies presented in this thesis. In the first case study (mid-term planning), the focus is on determining power plant’s optimal operating strategy, while taking into account the uncertainty in inflows and prices. Stochastic dynamic programming has been chosen as mid-term optimization technique. Since stochastic dynamic programming calls for a discretization of control and state variables, it may fall under the curse of dimensionality and therefore, the modeling of stochastic variables is important. By implementing a randomized search heuristic, a genetic algorithm, into the existing stochastic dynamic programming schema, the optimal way of using the stochasticity tries to be found. Two price models are compared based on the economic quality of the result. The results give support to the idea of using search heuristics to determine the optimal stochasticity setup, however, some deviations from the expected results occur. Second case study deals with short-term hydropower planning, with a focus on satisfying the predefined demand schedule while obtaining maximum profit. With short-term hydropower planning being a nonlinear and nonconvex problem, the main focus is on the linearization of unit performance curves, as well as satisfying technical constraints from the power plant perspective. This optimization techniques also includes the water value in the solution. The problem has been solved by means of mixed integer linear programming. The results from the second case study are fully in line with the expectations and it is shown that mixed integer linear programming approach gives good results with good computational time. Suggested improvements to the model and potential for future work can be found in the final chapter of this thesis.
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McCarthy, Donald. "Lubrication of sliding bearings for hydropower applications." Licentiate thesis, Luleå, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26457.
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The term "sliding bearing" refers to types of bearing where two conformal surfaces (usually the stationary bearing and a moving shaft) slide relative to one another with load distributed directly across the interface. A suitable lubricant may be employed to reduce the friction between these two surfaces. In "fluid film" bearings, this lubricant builds up a layer of sufficient thickness such that the two surfaces are completely separated. Examples include journal and thrust bearings and shaft bushings. Unlike ball or roller bearings which have a limited lifespan, sliding bearings have, at least in theory, an indefinite operational lifespan. As long as an oil film of sufficient thickness is maintained and contamination is avoided, the bearing may continue to do its job indefinitely. However, more and more onerous demands are being placed on such bearings and their associated methods of lubrication in order to maximise performance in terms of efficiency and load carrying capacity, for example in hydroelectricity generators and turbines. Given the sensitivity of operating any form of mechanical equipment in the vicinity of watercourses, often the source of drinking water for major population centres, the hydropower industry has a duty of responsibility in ensuring that as much as possible is done to minimise the risk of contamination of the water or damage to flora and fauna. Two aims - increased output, decreased environmental impact - are currently the major driving forces behind Research and Development in the hydroelectric power generation industry. Looking at these from a tribological (friction and lubrication) point of view, three areas of particular interest can be identified. These are: 1) How can the load carrying capacity of thrust bearings be increased whilst at the same time improving performance within existing dimensional constraints? 2) What is the influence on bearings of transient events (rapid changes in speed or loading) and what impact do they have on the machinery components? 3) How does the use of Environmentally Adapted Lubricants (as opposed to mineral oils) influence friction and wear etc, specifically with reference to shaft bushings, and what is the impact of fluid ageing (oxidation) on their performance? Each of these three points has been studied in the course of the work carried out for this thesis.<br>Godkänd; 2005; 20061214 (haneit)
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Lövgren, Magnus. "Time dependent pressure phenomena in hydropower applications." Licentiate thesis, Luleå tekniska universitet, Strömningslära och experimentell mekanik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16957.
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Time resolved pressure measurements in hydropower applications are of great interest. Different parts of the machine experience highly transient flows that influence the function and efficiency of the turbine. This thesis addresses different time dependent pressure phenomena. Assessment of the efficiency of a hydropower plant requires accurate flow measurements. Gibson's method is a pressure time based method to measure the flow rate. To improve the method outside its standard range an experimental investigation is performed in a laboratory setup in parallel with numerical solutions of the governing equations. The results indicate that it is possible to correct the flow measurements outside the limitations of the standard. A draft tube is an integrated part of a hydropower plant with a reaction turbine where the remaining kinetic energy of the flow after the turbine is converted into pressure. An experimental investigation is performed on a model hydropower draft tube at Älvkarleby to establish the details of the pressure recovery in the early part of the draft tube. The objective is to increase the understanding of the pressure behaviour and to contribute with data for CFD (Computational Fluid Dynamics) validations. The results show a high damping of the oscillating parts of the pressure in the axial direction. From earlier investigations done as part of the Turbine-99 workshops, it has been observed that the radial pressure distribution just under the turbine runner show a marked discrepancy between experiments and CFD. The flow in the region is highly time dependent so the behaviour of the Pitot tube used for the pressure measurements is investigated for oscillating flow in a lab setup. A method to derive more accurate data is proposed.<br><p>Godkänd; 2006; 20070109 (haneit)</p>
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Thiery, Florian. "Evaluation of strong nonlinearities in hydropower systems." Licentiate thesis, Luleå tekniska universitet, Material- och solidmekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26375.
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In hydropower systems, it is essential to avoid catastrophic failures that leads to human and economic losses. Unfortunately, the rotor can behave abnormally since several nonlinear effects occur during start-up, shut downs or when running at nominal speed. Weak nonlinear interaction in the tilting pad bearings, electromagnetic interaction between the generator and rotor or fluid-structure interaction in turbines are typical nonlinear effects that appear. Moreover, strong nonlinearities can also occur due to blade contacts and assembly errors. These types of nonlinearities can be strong in case of bad design of the rotor, and it could even lead to catastrophes in the worst case. Due to the complexity of the blade contact nonlinearity, it is first necessary to evaluate the general properties of the system using a simple model such as the Jeffcott rotor. Studies of nonlinearities are performed using common tools such as Poincare sections, bifurcation diagrams, Maximum Lyapunov Exponent, Lyapunov Spectrum and 3-dimensional plots of the Fast Fourier Transform . The results obtained are also compared with an experimental rig to validate the models proposed. The second part of the thesis is dedicated to real hydropower systems with complex geometry. A focus is made on the numerical methods to employ as well as reduction methods to gain computation time. The aim is to verify that the inherent properties of simple bladed are also present in complex systems. Further numerical simulations of the system at nominal speed will be studied as function of unbalance forces and damping properties. In this case, the tools used in simple rotors system can help us evaluate under which conditions a catastrophic failure can be avoided in any hydropower system.<br>Godkänd; 2014; 20140211 (flothi); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Florian Thiery Ämne: Hållfasthetslära/Solid Mechanics Uppsats: Evaluation of Strong Nonlinearities in Hydropower Systems Examinator: Professor Jan-Olov Aidanpää, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Diskutant: Professor Ilmar Santos, Technical University of Denmark, Lyngby, Denmark Tid: Torsdag den 20 mars 2014 kl 09.00 Plats: E243, Luleå tekniska universitet
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Gustavsson, Rolf. "Modelling and analysis of hydropower generator rotors /." Luleå, 2005. http://epubl.luth.se/1402-1757/2005/62.
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McCarthy, Donald M. C. "Lubrication of sliding bearings for hydropower applications /." Luleå, 2005. http://epubl.luth.se/1402-1757/2005/75.
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Lövgren, H. Magnus Lövgren [Hans] Magnus. "Time dependent pressure phenomena in hydropower applications /." Luleå : Luleå tekniska universitet/Tillämpad fysik, maskin- och materialteknik/Strömningslära, 2006. http://epubl.ltu.se/1402-1757/2006/30/index.html.
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Andersson, Mikael, and Leo Lingvide. "Possibilities for small scale hydropower in Honduras." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-22557.
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With an increased demand of electricity it is in everyone´s interest that investments are made to promote sustainable options, and the question on how to supply clean and sustainable energy is global. In this bachelor’s thesis, funded by SIDA and Åforsk, the intention was to investigate the possibilities for renewable energy in Honduras, a developing country with an expanding energy sector. Honduras is Central America´s second largest country, located in-between Guatemala, Nicaragua and El Salvador. The country is one of poorest in the region, and the trade is characterized by the import of oil and export of coffee and fruit. Hydropower has played a major role in the development of the Honduran electricity sector, but today oil based thermal power has the largest share of the energy market. It accounts for more than half of the total generation which makes Honduras very vulnerable to changes in the oil price. The remaining share of generation comes from renewable sources, mostly hydropower. The potential for hydropower in Honduras is estimated to be about five times bigger than the current installed capacity. With a constantly rising oil price, building new hydropower or refurbishing old is becoming more and more competitive. This is the reason for this thesis; to investigate the possibilities for small scale hydropower in Honduras. Information has been gathered through contacts with energy organizations as well as examples and experiences from refurbished or upgraded hydropower plants and other relevant hydropower projects. With this information barriers and possibilities in the process of refurbishing, upgrading and building hydropower plants in Honduras have been identified. Our conclusion is that developing small scale hydropower in Honduras is very demanding; applying for required permissions, studies, financing, construction etc. are barriers which all require hard work. Considering this we still believe that the possibilities and positive impacts are greater than the barriers and negative impacts when developing small scale hydropower in Honduras thanks to legislated incentives. The positive impacts that can come from building and refurbishing hydropower plants include: cheaper electricity, improved roads, power lines, and schools, promotion of rural electrification and creation of new job opportunities. Small scale hydropower can help Honduras use its natural resources and create a sustainable development for a brighter future.<br>Med ett ökat behov av elektricitet ligger det i allas intresse att satsningar görs på hållbara alternativ. Jakten på ren och hållbar energi är därför en global fråga aktuell för alla delar av världen. Detta examensarbete, finansierat av SIDA och ÅForsk, har för avsikt att undersöka möjligheterna för förnybar energi i Honduras, ett utvecklingsland vars energisektor är i en expansiv fas. Honduras är Centralamerikas näst största land, beläget mellan Guatemala, Nicaragua och El Salvador. Landet är ett av de fattigaste i regionen med en handel som kännetecknas främst av oljeimport och export av kaffe och frukt. I utvecklingen av Honduras elsystem har vattenkraft spelat en stor roll, men den har förlorat marknadsandelar till förmån för oljebaserad värmekraft. I dagsläget utgör värmekraft mer än hälften av Honduras elproduktion vilket gör landet mycket sårbart för förändringar i oljepriset. Resterande elproduktion utgörs av förnybar energi, till största del vattenkraft. Potentialen för vattenkraft i Honduras uppskattas till nästan fem gånger den idag installerade effekten. Med stigande oljepriser blir det mer konkurrenskraftigt att bygga nya vattenkraftverk eller göra upprustningar av äldre. Med anledning av detta syftar den här rapporten till att undersöka förutsättningarna för småskalig vattenkraft i Honduras. Genom kontakt med energiorganisationer samt exempel och erfarenheter från redan upprustade, uppgraderade eller andra relevanta projekt inom vattenkraft har information insamlats. På så vis har barriärer och möjligheter i processen att upprusta, uppgradera och bygga vattenkraftverk i Honduras identifierats. Vår slutsats är att det krävs en stor insats att utveckla småskalig vattenkraft i Honduras, ansökningar för efterfrågade tillstånd, studier, finansiering, konstruktion och så vidare är barriärer som alla kräver hårt arbete för att övervinnas. Vi anser dock att möjligheterna tack vare lagstiftade incitament och positiva effekter av att utveckla småskalig vattenkraft i Honduras överväger barriärerna och de negativa effekterna. Byggnation och upprustning av vattenkraftverk kan ha positiva följder såsom billigare el, upprustning av vägar, kraftledningar, skolor, främja elektrifiering och skapa arbetstillfällen på landsbygden. Småskalig vattenkraft kan därför hjälpa Honduras att ta till vara på sina naturtillgångar och skapa en hållbar utveckling för en ljusare framtid.
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Wang, Katherine. "Hydropower: The Giant of Renewable Electricity Production." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190833.
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The growing environmental awareness and simultaneous increase in electricity consumption calls for cleaner production methods. With the help of effective energy storage techniques, more sustainable electricity production methods can be used. In the current market hydropower is the most mature renewable energy storage technology and stands for 16.3% of the world’s total electricity production. Hydropower is heavily dependent on water resources and the construction projects can cause different negative impacts. The objective of this paper is to give an overview of the factors of effect hydropower projects can give. The consequences are divided into three categories: environmental, social and economic. Two different cases are going to set the basis of the discussion, the market in an already developed country such as Norway and a fast developing market that can be found in China. The scenarios are very different from each other because of their diverse backgrounds. One of the key learnings is the importance of assessing every hydropower project individually depending on its unique situation and at the same time use learnings from previously completed projects with similar profiles. As technology advances, better solutions for the current problems are going to be developed and better hydropower project planning will evolve it into an even more sustainable energy source. Hydropower is and will continue to be a competitor in the electricity market.<br>I det moderna samhället finns det ett växande intresse för bevarandet av miljön. Samtidigt ökar konsumtionen av elektricitet konstant. För att detta ska vara hållbart utvecklas ständigt nya metoder av miljövänligare elektricitetsproduktion. Energilagringstekniker gör det möjligt att tillämpa tekniker såsom sol- och vindkraft effektivt. I dagsläget står vattenkraft för 16.3% av den globala elektricitetsproduktionen och står för den största andelen av producerad förnybar energi i världen. Eftersom vattenkraft är starkt beroende av tillgången på vattendrag och specifik terräng kan det orsaka negativ påverkan på omgivningen. Målet med denna rapport är att ge en överblick av de faktorer som kan påverka effekterna av vattenkraftverk. Konsekvenserna är indelade i tre kategorier: miljömässiga, social påverkan och ekonomiska effekter. Två olika vattenkraftsmarknader sätts som grund till diskussionen. Norge som är ett välutvecklat land med en mycket mogen vattenkraftsmarknad och Kina som är ett snabbt utvecklande land utan ett stabilt system ännu för hur vattenkraft ska hanteras. Länderna har bland annat helt skilda ekonomiska och sociala bakgrunder vilket gör de mycket olika och intressanta att jämföra. En viktigaste lärdom är den starka betydelsen att bedöma varje vattenkraftsprojekt individuellt men samtidigt ta lärdom av tidigare likartade utförda projekt. Med teknikens framgång kommer förbättrade lösningar för nuvarande problem att utvecklas. Både tekniska lösningar och mer raffinerad projektplanering kommer göra vattenkraft till en ännu mer miljömässigt hållbar energikälla. Vattenkraft är och kommer fortsätta vara en mycket betydelsefull teknik på elektricitetsmarknaden.
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Bitar, Nádia Matioli Yazbek. "Hydropower plants: a mosaic of landscape heritage." Master's thesis, Universidade de Évora, 2018. http://hdl.handle.net/10174/24354.
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Cette recherche a abordé différentes manières de penser et d'agir sur le paysage des centrales hydroélectriques. Il vise à identifier comment des paysages particuliers (et compris en tant que patrimoine) sont traités dans différents cas et situations dans le monde où l’industrie des barrages s’impose et se réinvente. Pour cela, le travail reprend les concepts de paysage présents dans les débats théoriques de la géographie, mais en dialogue avec d'autres domaines, tels que les arts, la littérature ou l'ingénierie, compte tenu du potentiel de ce concept à catalyser des approches interdisciplinaires. La méthodologie proposée est basée sur l'inventaire des différents cadres (politiques, esthétiques, écologiques, éthiques) à un exercice à l'identification des particularités, mais aussi des déterminations générales qui se chevauchent l'espace habité (écoumène) face à des projets d'une telle ampleur. Ainsi, la proposition d'une mosaïque de paysages hydroélectriques destinés à évoquer la discussion entre le local et le global; exposer des scénarios critiques qui se répètent dans le monde et qui, d'un autre côté, ont permis de révéler des expériences et des sensibilités qui indiquent d'autres perspectives, peut-être plus encourageantes; Este trabalho abordou diferentes formas de pensamento e atuação sobre a paisagem das Centrais Hidrelétricas. Procurou identificar como uma paisagem tão singular (e entendida como um património) é tratada em diferentes casos e situações no mundo onde a indústria das barragens se impõe e se reinventa. O trabalho resgata conceitos de paisagem que estão presentes nos debates teóricos da geografia, mas que dialogam com outros campos, como as artes, literatura ou engenharia devido ao potencial deste conceito em catalisar abordagens interdisciplinares. A metodologia proposta baseia-se e inventários feitos em diferentes contextos (político, estético, ecológico, ético) como exercício de identificação das particularidades, mas também de determinações gerais que se sobrepõem ao espaço habitado (ecúmeno) pressionados em face de projetos de tal magnitude. Assim, a proposição de um mosaico de paisagens de hidroelétricas procurou despertar a discussão entre o local e o global, expondo cenários críticos que se repetem no mundo e que por outro lado também permitiram revelar experiências e sensibilidades que apontam para a outras perspectivas, talvez mais animadoras; Abstract: This research approached different ways of thinking and acting on landscape of Hydroelectric Power Plants. It aimed to identify how a landscape so unique (and understood as a heritage) is treated in different cases and situations in the world where the dam industry imposes and reinvents itself. For this, the work rescues concepts of landscape present in the theoretical debates of geography, but that dialogue with other fields, such as the arts, literature or engineering, given the potential of this concept to catalyze interdisciplinary approaches. The proposed methodology is based on inventories of different framework (political, aesthetic, ecological, ethical) as an exercise in the identification of particularities, but also of general determinations that overlap the inhabited space (ecumene) in the face of projects of such magnitude. Thus, the proposition of a mosaic of hydroelectric landscapes intended to awaken the discussion between the local and the global, exposing critical scenarios that are repeated in the world and that, on the other hand, also allowed to reveal experiences and sensibilities that point to other perspectives, perhaps more encouraging.
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Prianto, Pandu Nugroho. "Equivalent Models for Hydropower Operation in Sweden." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302777.
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Hydropower systems often contain complex river systems which cause the simulations and analyses of a hydropower operation to be computationally heavy. The complex river system is referred to as something called a Detailed model. By creating a simpler model, denoted the Equivalent model, the computational issue could be circumvented. The purpose of this Equivalent model is to emulate the results of the Detailed model. This thesis computes the Equivalent model for a large hydropower system using Particle Swarm Optimisation- algorithm, then evaluates the Equivalent model performance. Simulations are performed on ten rivers in Sweden, representing four trading areas for one year, October 2017 – September 2018. Furthermore, the year is divided into Quarterly and Seasonal periods, to investigate whether the Equivalent model changes over time. The Equivalent model performance is evaluated based on the relative power difference and computational time compared to the Detailed model. The relative power difference is 4%23% between Equivalent and Detailed models, depending on the period and trading area, with the computational time can be reduced by more than 90%. Furthermore, the Equivalent model changes over time, suggesting that when the year is divided appropriately, the Equivalent model could perform better. The relative power difference results indicate that the Equivalent model performance can still be improved by dividing the periods more appropriately, other than Quarterly or Seasonal. Nevertheless, the results provide a satisfactory Equivalent model, based on the faster computation time and a reasonable relative power difference. Finally, the Equivalent model could be used as a foundation for further analyses and simulations.<br>Vattenkraftsystem består ofta av komplexa älvsystem som gör att simuleringar och analyser av vattenkraftens operation blir beräkningsmässigt tunga. Det komplexa älvsystem kallas en Detaljeraded modell. Genom att skapa en enklare modell, betecknas som en Ekvivalent modell, beräkningsproblemen kan kringgås. Syftet med denna Ekvivalenta modell är att emulera resultaten av den komplexa Detaljerade modellen. Detta examensarbete beräknar den Ekvivalenta modellen för ett stort vattenkraftssystem med hjälp av Particle Swarm Optimisation- algorithmen, och utvärderar modellprestandan hos Ekvivalenten. Simuleringar utförs på tio älvar i Sverige, som representerar fyra handelsområden under ett år, från oktober 2017 september 2018. Dessutom är året uppdelat i kvartals- och säsongsperioder för att undersöka om den Ekvivalenta modellen förändras över tid. Denna Ekvivalenta modell utvärderas baserat på den relativa effektskillnaden och beräkningstiden jämfört med den Detaljerade modellen. Den relativa effektskillnaden är 4% 23% mellan de Ekvivalenta och Detaljerade modellerna, beroende på period och handelsområde, och beräkningstiden minskas med mer än 90%. Vidare ändras Ekvivalenta modellen över tiden, vilket tyder på att när året delas upp på rätt sätt kan den Ekvivalenta modellen prestera ännu bättre. De relativa effektskillnaderna indikerar att vissa perioder fortfarande kan förbättras genom att dela upp perioden mer korrekt. Trots allt, förser resultanten en tillfredsställande Ekvivalent modell som har en mer effektiv beräkningstid och rimliga effektskillnader. Slutligen skulle den Ekvivalenta modellen kunna användas som en grund för ytterligare analyser och simuleringar.
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Towle, Anna-Linnea. "Optimal Production Planning for Small-Scale Hydropower." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-235266.
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As more and more renewable energy sources like wind and solar power are added to the electricgrid, reliable sources of power like hydropower become more important. Hydropower isabundant in Scandinavia, and helps to maintain a stable and reliable grid with added irregularitiesfrom wind and solar power, as well as more fluctuations in demand. Aside from the reliabilityaspect of hydropower, power producers want to maximize their profit from sold electricity. InSweden, power is bid to the spot market at Nord Pool every day, and a final spot price is decidedwithin the electricity market. There is a different electricity price each hour of the day, so it ismore profitable to generate power during some hours than others.There are many other factors that can change when it is most profitable for a hydropower plant tooperate, like how much local inflow of water there is. Hydropower production is an ideal case forusing optimisation models, and they are widely used throughout industry already. Though theoptimisation calculations are done by a computer, there is a lot of manual work from the spottraders that goes into specifying the inputs to the model, such as local inflow, price forecasts, andperhaps most importantly, market strategy. Due to the large amount of work that needs to be donefor each hydropower plant, many of the smaller power plants are not optimised at all, but are leftto run on an automatic control that typically tries to maintain a constant water level. In Fortum,this is called, VNR, or vattennivåreglering (water level regulation).The purpose of this thesis is to develop an optimisation algorithm for a small hydropower plant,using Fortum owned and operated Båthusströmmen as a test case. An optimisation model is builtin Fortum’s current modelling system and is tested for 2016. In addition, a mathematical model isalso built and tested using GAMS. It is found that by optimising the plant instead of running it onVNR, an increase of about 15-16% in profit could be seen for the year 2016. This is a significantimprovement, and is a strong motivator to being optimising the small hydropower plants.Since the main reason many small hydropower plants are not optimised is because it takes toomuch of employees time, a second phase of this thesis was conducted in conjunction with twoother students, Jenny Möller and Johan Wiklund. The focus of this portion was to develop acentralized controller to automatically optimise the production schedule and communicate withthe central database. This would completely remove the workload from the spot traders, as wellas increase the overall profit of the plant. This thesis describes the results from both the Fortummodel and the GAMS model, as well as the mathematical formulation of the GAMS model. Thebasic structure of the automatic controller is also presented, and more can be read in the thesis byMöller and Wiklund (Möller & Wiklund, 2018).<br>Tillförlitliga energikällor som vattenkraft blir allt viktigare vart eftersom elkraftsystemet utökasmed fler förnybara energikällor som vindkraft och solenergi. I Norden finns det rikligt medvattenkraft, vilket bidrar till att upprätthålla ett stabilt och pålitligt elnät även med ökadeoregelbundenheter från vindkraft och solkraft samt större variationer i efterfrågan. Bortsett frånvattenkraftens tillförlitlighetsaspekter vill kraftproducenter maximera sin vinst från såld el. ISverige läggs dagligen bud på effektvolym till spotmarknaden Nord Pool och ett slutgiltigtmarknadspris bestäms därefter av elmarknaden. Varje timme under dygnet motsvarar ett enskiltelpris, därmed är det mer lönsamt att generera effekt under de timmar där priset är som högst.Det finns många andra faktorer som påverkar när det är mest lönsamt för ett vattenkraftverk attproducera el, exempelvis hur stort det lokala inflödet av vatten är. Vattenkraftproduktion är idealtför tillämpning av optimeringsmodeller, vilka är vanligt förekommande inom verksamhetsområdet.Även om optimeringsberäkningarna utförs av en dator innebär optimeringen mycket manuelltarbete för Fortums elhandlare som specificerar indata till modellen. Exempel på indata är lokaltinflöde, prisprognoser och kanske viktigast av allt marknadsstrategi. På grund av den storamängden arbete som fordras för varje vattenkraftverk, optimeras inte produktionen för många avde småskaliga kraftverken utan de regleras automatiskt med mål att upprätthålla en konstantvattennivå. Denna typ av reglering kallas vattennivåreglering, VNR.Syftet med examensarbetet var att utveckla en optimeringsalgoritm för ett småskaligtvattenkraftverk, där Fortumägda vattenkraftverket Båthusströmmen används som testobjekt. Enoptimeringsmodell utvecklades i Fortums befintliga system och testades för 2016. Dessutom haren matematisk modell utvecklats och testades med GAMS. Det konstaterades att genom attoptimera produktionen från vattenkraftverket istället för att reglera den via VNR kan envinstökning med cirka 15-16 % för noteras år 2016. Detta är en väsentlig förbättring och är ettstarkt argument för att optimera produktionen från småskaliga vattenkraftverk.Eftersom den främsta orsaken till att många småskaliga vattenkraftverk inte optimeras är denutökade arbetsbelastningen det skulle innebära för de anställda, genomfördes en andra fas iexamensarbetet i samverkan med två andra studenter, Jenny Möller och Johan Wiklund. Fokus fördenna del var att utveckla en centraliserad styrenhet för att automatiskt optimera produktionsplaneroch kommunicera med det befintliga centrala systemet. Detta innebär att utökad arbetsbelastningenfrån elhandlarna undviks, samt öka vattenkraftverkets totala vinst. Denna rapport beskriverresultaten från både Fortum-modellen och GAMS-modellen, liksom den matematiskaformuleringen av GAMS-modellen. Även grundstrukturen för det självreglerandeoptimeringsverktyget presenteras, mer kan läsas i rapporten av Möller och Wiklund (Möller &Wiklund, 2018).Nyckelord: Optimering, vattenkraftplanering, självreglerande, automatisk styrning, optimalplanering
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MacArthur, Shona. "Bubbles guide migrating smolts around hydropower plants." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-160490.
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The development of hydroelectric power production and the damming of water courses that ensues causes a threat to the migration patterns of Atlantic salmon (Salmo salar), by altering their habitat and compromising river connectivity. Because the species’ survival heavily depends on the completion of their migration between rivers and oceans, the design of guidance structures that promote successful passages around dams is a critical goal. Physical structures have been used to steer downwards-migrating smolts through safe fishways but they have not always proven effective, both from an ecological and economical perspective. In this study, the potential of bubbles in guiding salmon trajectories around a hydropower dam was tested as an alternative to existing guiding systems. Here the hypotheses were: i) bubbles guide downstream-migrating smolts around dams; ii) the reaction of smolts to a bubble barrier is linked to their individual boldness; iii) bubbles have varying effects on different school sizes. The first and third hypotheses were tested in the field, by recording sonar footage at the entrance of a fishway, downstream of a bubble barrier. The second hypothesis was evaluated by conducting a scototaxis experiment and an assessment of the reaction of young salmon to bubbles in the laboratory. My analysis of the fish abundance data collected in the river confirmed the first and third hypotheses. In the field, the presence of a predator (Esox lucius) was revealed to be a more influential factor than bubbles in regulating the number of smolts steered towards the fishway, indicating that predators generated a larger anxiety-like response in smolts than bubbles. In the controlled laboratory setting, there was no significant correlation between anxiety-like behaviour and reaction to bubbles and the second hypothesis did not appear to be valid. Therefore, the cause of avoidance of the barrier remains unclear, but bubble barriers seem to be an efficient and cost-effective structure for guiding downstream-migrating salmon smolts.
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Movahedinia, Fatemeh. "Assessing hydro-climatic uncertainties on hydropower generation." Master's thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25294.
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Dans le cadre de ce travail, nous avons quantifié l’impact des incertitudes hydrologiques et climatiques sur la production hydroélectrique dans le bassin de la rivière Gatineau. L’approche mise en œuvre repose sur des simulations climatiques, la modélisation hydrologique et l'optimisation de l'exploitation des réservoirs. Les résultats hydrologiques confirment ce que d’autres études ont déjà montré, à savoir un hydrogramme plus contrasté, marqué par une fonte des neiges plus précoce et un volume de crue plus important, suivi d’une saison estivale plus sèche que par le passé. En termes de production d’énergie, cela se traduit par une production attendue d’énergie supérieure mais également plus variable. Ce gain d’énergie se produit essentiellement à la fin de l’hiver-début du printemps et fait suite aux précipitations plus importantes sur le bassin au cours de l’hiver. Compte tenu des caractéristiques physiques du système (capacités de stockage et de turbinage), les modifications du régime hydrologique entrainent des déversements supplémentaires, essentiellement pendant la fonte des neiges.<br>This research quantifies the impact of hydrological and climatic uncertainties on hydropower generation in the Gatineau River basin. The proposed approach is based on climate simulations, hydrological modeling and optimization of reservoir operation. Hydrological results from this study confirm what other studies have shown, a more mixed hydrograph marked by earlier snow melting and greater flood volume, followed by drier summers than in the past. In terms of energy production, this translates into an expected increase in energy but also in a more variable production. This gain of energy mainly occurs in the late winter-early spring and follows the higher rainfall in the basin during the winter. Given the physical characteristics of the system (storage and turbine capacity), changes in the hydrological regime entail additional spills, mainly during snowmelt.
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Dahlborg, Elin. "Grid frequency stability from a hydropower perspective." Licentiate thesis, Uppsala universitet, Elektricitetslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-444453.
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Many AC grids suffer from decreased frequency stability due to less system inertia. This has increased the risk of large-scale blackouts. This thesis and its papers address the frequency stability problem from a hydropower perspective. Grid frequency stability assessments often require accurate system inertia estimates. One approach is to estimate the inertia of all individual power plants and sum up the results. We implemented three inertia estimation methods on a Kaplan unit and compared their results. The generator contributed with 92-96% of the unit inertia, which verified the results from previous studies. However, the three methods estimated slightly different values for the unit inertia, which raises the question of when to use which method. Hydropower often deliver frequency control, yet we found no studies which validate Kaplan turbine models for large grid frequency disturbances on strong grids. Therefore, we performed frequency control tests on a Kaplan unit, implemented three hydropower models, and compared the simulation results to the measurement data. The models overestimated the change in output power and energy delivered within the first few seconds after a large change in frequency. Thus, it is important to have sufficient stability margin when using these types of hydropower models to assess the grid frequency stability. The Nordic transmission system operators are updating their frequency control requirements. We used measurement data and simulation models to assess whether improved runner blade angle control could help a Kaplan unit fulfill the coming requirements. The results showed that improved runner control does not improve the performance sufficiently for requirements fulfillment. The requirements are based on an assumption on minimum system inertia and became easier to fulfill if they were implemented with more system inertia. Thus, more inertia could allow more participants to deliver frequency control in the Nordic grid.
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Al, Tamimi Abdulsalam. "Feasibility study of hydropower system in Oman." Thesis, Al Tamimi, Abdulsalam (2018) Feasibility study of hydropower system in Oman. Honours thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/44794/.
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Reducing environmental and health impacts of using fossil fuel are the main concerns in the majority of countries which resulted in shifting from the use of fossil fuels (e.g., coal, oil, natural gas) to renewable energy (e.g., solar, wind, water) for electricity generation. The use of renewable energy sources is becoming more popular in the majority of Middle Eastern countries, particularly in Oman. In Oman, the use of renewable energy to produce electricity is rapidly growing considering that renewable energy will reduce the use of fossil fuel as the major source of energy. Hydropower is an important renewable energy resource globally. However, the feasibly of a hydropower plant in Oman has not been investigated. Therefore, the purpose of this project was to determine the feasibility of hydropower which can be installed in the Wadi Dayqah dam in Oman. The objectives are to explore the potential power to be harvested by hydropower, to assess financial saving and cost analysis and to investigate the environmental impact of hydropower in Oman.
The RETScreen expert was used to assess the feasibility of a hydropower system and to recommend the possibility of installing the system in the Wadi Dayqah Dam in Oman. The RETScreen expert is a Clean Energy Management Software developed by the Government of Canada which is a free-of-charge decision support software for pre-feasibility or feasibility analysis and also ongoing energy efficiency performance analysis.
In this project, two cases have been analysed. For the case one (the design flow was 0.3 m3/s, and installed capacity was 110 kW), the RETScreen analysis showed estimated cost 338,000 AUD, annual savings and revenue 57,165 AUD and Gross Annual GHG reduction 605.3 tCO2/year. For the case two (the design flow was 13 m3/s, and installed capacity was 5 MW), the RETScreen analysis demonstrated the estimated cost 6,204,000 AUD, annual savings and revenue 1,802,747 AUD and Gross Annual GHG reduction 19,090.1 tCO2/year.
Overall, this project indicated that the use of the hydropower system in the Wadi Dayqah Dam in Oman is viable regarding technical, economic, and environmental aspects.
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Pacheco, Gomez Rodolfo Guillermo. "Effect of climate change in hydropower generation." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289226.
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Impact of potential climatic change in hydropower generation has been the main objective of this research. Two flood control, hydropower, and recreation projects located in the midwest USA have been selected as the subject of the analysis given the consistency of the available climatic data and the adequate energy generation records. These two reservoirs are Stockton and Harry S. Truman Reservoirs located on the Osage River Basin which is part of the Lower Missouri River Basin. Both reservoirs were designed, constructed and are currently managed by the U.S. Army Corps of Engineers, Kansas City District. Long-term monthly precipitation, evaporation, temperature, streamflow and power generation records were used in the statistical analysis. The hydrologic data, precipitation, temperature, and streamflow data were utilized in a multivariate analysis with the purpose of producing a regression model capable of reproducing baseline conditions. From the baseline conditions, ten different climatic variation scenarios were studied. Each scenario produced a series of streamflow records that were extended using a randomly generated data to produce 21-year long reservoir inflow series. Reservoir inflow series in each scenario were modeled using a reservoir operation model. Firm energy was then evaluated and compared with baseline conditions to determine the economic impact of the climatic variations. In summary, operating rules and water reservoir management for different purposes are impacted and need further evaluation by operating managers, if streamflow records were to follow studied trends.
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Brenes, Brenes Rebeca. "Hydropower Modelling of Continental Europe Using EMPS." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-261790.
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Flexible hydropower plays a vital role when integrating large shares of variablerenewable generation in the power system. This project proposes a method forcreating a stochastic model for hydropower in Continental Europe using EMPS, apower market simulator software that specialises on hydrothermal power systems.The model is intended to be used in a power market analysis context, to assess thehydropower behaviour in Continental Europe in the medium and long term.The first step to create the model was to gather data from multiple sources regardinghydropower stations and reservoirs located in Continental Europe. The gathereddata was built and unified into a geographical information system to provide visualanalysis and facilitate performing of different operations and algorithms. Thecountries under study were split into different areas depending on the water basinsand other location factors. Representative inflow series were created for each area,and these were fed directly into EMPS. The stations and reservoirs were aggregatedper area and the inputs required by EMPS were calculated using a model based onhistorical data and an optimisation process.The model provides results for 45 different weather scenarios. The hydropowergeneration and reservoir content for each country were validated using historicaldata. In general, the results obtained provide a satisfactory representation of thehydropower in the region under study. Fine tuning is still required to improve theresults, but this project successfully provides a solid method to create the core ofthe stochastic hydropower model of Continental Europe in EMPS.<br>Flexibel vattenkraft är grundläggande för reglering i elkraftsystem med en stormängd variabel förnybar elproduktion. Detta projekt föreslår en metod för attskapa en stokastisk modell av vattenkraftproduktion i Kontinentaleuropa medEMPS, en mjukvara som simulerar elmarknaden och optimerar produktion i systemmed både vattenkraft och kraftvärme. Modellen är avsedd för att användas tillelmarknadsanalys, för att utvärdera vattenkraftens beteende i Kontinentaleuropapå medellång och lång sikt.Första stegen för att skapa modellen var att samla information från olikakällor om vattenkraftverken och magasinen i Kontinentaleuropa. Den insamladeinformationen byggdes in i ett gemensamt geografiskt informationssystem. Dettaför att underlätta visualisering och utföra operationer med datan. Ländernasom studerades delades in i olika områden beroende på vattendrag och andrageografiska faktorer, inklusive avrinningsområden. Representativa inflöden skapadesför varje område, och användes som indata till EMPS. Kraftverken och magasinenaggregerades utefter område. Indata för EMPS beräknades med en modell baseradpå historiska data och en optimeringsprocess.Modellen ger resultat för 45 olika väderscenarion. Vattenkraftsproduktionen ochnivån i magasinen för varje land validerades med historisk data. Generelltär de erhållna resultaten en bra representation av vattenkraft i alla områdensom studerades. Modellen behöver finjusteras för att förbättra resultaten, mendetta projekt ger en solid metod som fungerar som kärnan till den stokastikavattenkraftmodellen av Kontinentaleuropa i EMPS.
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Del, Bene Daniela. "Hydropower and ecological conflicts. From resistance to transformations." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/664010.
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El sector hidroeléctrico está pasando por una fase de expansión a nivel global, siendo promovido como una fuente de energía sostenible y renovable. Sin embargo, la construción de represas está causando un creciente número de conflictos ambientales debido a sus impactos ecológicos y sociales. Al mismo tiempo, activistas y comunidades afectadas se organizan en movimientos sociales y redes internacionales para denunciar impactos y violencia en sus territorios.
Hasta la fecha, la investigación se ha centrado en gran medida en evaluar los impactos específicos de las grandes represas y la oposición asociada que ha surgido. Esta tesis critica la reciente expansión de la energía hidroeléctrica que se está legitimado a través de un discurso de sostenibilidad, toma una perspectiva territorial y se centra en las fuerzas transformadoras que surgen de los movimientos sociales anti-represas. Esta tesis adopta el abordaje de la ecología política y de la economía ecológica, bajo el enfoque de la investigación activista para abordar tres dimensiones principales de la resistencia anti-represas.
Primero, esta tesis investiga la expansión del sector hidroeléctrico a lo largo de una reciente frontera extractiva, el estado Himalayano de Himachal Pradesh en la India. Esta investigación se realizó en colaboración con activistas locales e investigadores independientes, a través de un mapeo regional participativo de 17 casos de conflicto, utilizando el EJAtlas (Atlas Mundial de Justicia Ambiental). Se analizan los actores involucrados y los lenguajes de valoración de los afectados que protestan y se movilizan, incluyendo las preocupaciones por los impactos ecológicos, la violación de leyes, y el carácter violento de la expansión del sector hidroeléctrico. Finalmente, se discuten las energías renovables de gran escala como adicionales impulsoras de un ‘extractivismo de las renovables’, promovido por el discurso de la energía limpia, y un ‘consenso de las infraestructuras’, paralelo al ‘consenso de los commodities’.
Segundo, esta tesis adopta el abordaje de la ecología política comparativa para investigar los patrones de la represión violenta de las protestas anti-represas a nivel mundial. Se analizan 220 casos de conflictos por represas hidroeléctricas incluídos en el EJAtlas, focalizando principalmente en cuatro categorías de ‘Outcomes’ (represión violenta de la protesta, criminalización, persecución violenta de activistas, y asesinatos); así como también se destacan los grupos movilizados, sus formas de movilización, y los impactos socio-económicos, ambientales y de salud más frecuentemente reportados. Esta sección muestra cómo la violencia aumenta de forma específica en territorios indígenas, y cómo la represión no solamente se dirige a la oposición a determinados proyectos, sino que también se busca deslegitimar otras formas de relacionarse con el territorio, otras visiones del mundo, y otras ontologías.
Tercero, esta tesis discute cómo los movimientos anti-represas juegan un rol importante en la generación de fuerzas transformadoras que nacen desde la resistencia. Esta sección se basa en entrevistas a líderes activistas y a miembros de comunidades, y en la participación personal en redes de activistas. Se argumenta que, en respuesta a procesos de acaparamiento de tierra, agua y energía (es decir, de soberanía) por parte de la industria hidroeléctrica, los movimientos apelan de manera creciente a: trabajar transversalmente los temas (tierra, agua, energía) para superar la sectorializacion de los movimientos sociales; ampliar la forma de entender los ‘impactos’ y pasar del concepto de ‘afectado por proyecto’ a ‘afectado por el modelo (energético)’, aumentando el alcance de la resistencia; comprometerse en una lucha epistémica por el reconocimiento de formas plurales de comprender la tierra, el agua y la energía. Esta sección finalmente presenta la ‘soberanía energética’ como un eslogan emergente de la resistencia anti-represas y, por consiguiente, del vocabulario de la justicia ambiental, que reivindica el control popular sobre modelos energéticos y diversas ‘territorialidades’.<br>Hydropower is undergoing a new construction boom globally and is increasingly promoted as a sustainable and renewable source of energy. Yet construction of hydroelectric dams results in a growing number of ecological conflicts due to both ecological and social impacts. In response, impacted communities and activists are mobilising in social movements and international networks. To date, social research has largely focused on assessing the project-specific impacts of large dams and the associated opposition that has arisen.
This research critiques the recent expansion of hydropower that is being legitimised through a discourse of sustainability, takes a territory-wide perspective and focuses on the transformative forces that arise from within anti-dam social movements. This thesis adopts the lens of political ecology and ecological economics and an activist-led research approach to investigate three main dimensions of anti-dam resistance.
First, this thesis examines the expansion of hydropower along one recent commodity extraction frontier, the Himalayan state of Himachal Pradesh in India. This research was done in collaboration with local activists and independent researchers and through participatory regional mapping of 17 cases of conflict using the Global Atlas of Environmental Justice – EJAtlas. It analyses the actors involved and the valuation languages of the impacted communities who protest and mobilise, including concerns over disruption of local ecologies, violation of laws, and the violent character of hydropower expansion. It finally discusses imposed large-scale renewables as additional drivers of a ‘renewables’ extractivism’ promoted as sustainable green energy and by a ‘consensus of infrastructures’, parallel to a ‘consensus of commodities’.
Secondly, this thesis adopts a comparative political ecology approach to inquiry trends and patterns of violent repression of the anti-dam protest globally. It analyses 220 cases of ecological conflicts over hydroelectric dams included in the EJAtlas database, focusing on four main categories of the ‘Outcomes’ namely violent repression of protests, criminalization, violent targeting of activists and assassinations, as well as the types of groups mobilizing, the forms of mobilization, and the most frequently reported socio-economic, environmental and health impacts. This section shows how violence particularly increases in Indigenous territories and how repression not only targets the opposition to specific projects but aims at delegitimising other and different relations to the territory, world-visions, and ontologies.
Thirdly, this dissertation discusses how anti-dam movements play a central role in the production of forces for transformation that are born out of the resistance. This section is based on interviews with lead activists and community members and through personal participation in activist networks. It argues that in response to the land, water and energy grabbing (alias, sovereignty grabbing) caused by the hydropower industry, movements increasingly call for resistance to: ‘scale out’ across sectors (land, water and energy) to overcome the sectorialisation of social movements; expand the understanding of impacts, not only referring to ‘project-affected’ but to ‘(energy)model-affected people’, in order to widen the outreach of resistance; engage in an epistemic struggle for the recognition of a pluralistic understanding of land, water and energy. This section finally presents ‘energy sovereignty’ as an emerging slogan of anti-dam resistance and thus of the vocabulary of environmental justice to reclaim people’s control over different energy models and diverse and other ‘territorialities’.
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Vardanyan, Yelena. "On stochastic optimization for short-term hydropower planning." Licentiate thesis, KTH, Elektriska energisystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-104638.
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Renewable generation is the fastest growing energy resources in the past decade. Renewable energy sources, particularly wind power, provide clean and environmentally friendly energy to meet the system demand, meanwhile introducing huge levels of uncertainty in the system. On the one hand the deregulated electric power industry and on the other hand the intermittent nature of renewable energy sources cause highly volatile and uncertain electricity prices in different market places. This will create challenges for economical operation and planning of the flexible energy sources, particularly hydropower, which being a flexible energy source is the best option to balance wind power variation. The main purpose of this work is to develop optimal short-term planning models for price taker hydropower producer working in the existing environment. Those models have to deal with the huge level of uncertainties the wind power introduces into the power system. An optimization tool known as stochastic optimization is used to plan hydropower production under uncertainties. The first model, which is used to make sensitivity analysis, is a twostage stochastic linear programming problem. The uncertainties are handled by generating scenarios based on historical data. Profound sensitivity analysis is provided, in terms of volatility in day-ahead market prices and water inflow level as well as in terms of water opportunity cost and initial volume of the reservoir. Based on the comparison of the stochastic and corresponding deterministic problems, the result aims to show the impact of modeling the uncertainties explicitly. The results show that for the short-term hydropower planning problems the effect of considering price uncertainty in the stochastic model is higher compared with considering inflow level uncertainty. The second model used in this work is a two-stage stochastic linear programming problem. The model generates optimal bids to day-ahead market considering real-time market price uncertainties. While simultaneously bidding to both markets, the results for most of the hours suggest two actions; either to bid the available amount of energy to upward regulation market or to bid the maximum capacity to day-ahead market and bring back the whole amount making down regulation. To make the bidding strategies more flexible and robust different approaches are modeled and assessed. Finally one of the approaches is suggested as the most applicable one.<br><p>QC 20121109</p>
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Vogt-Svendsen, Simen Nordre. "Simulation Program for Stability Analysis of Hydropower Plants." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18602.
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Over the last few years Norway has seen an increasing number of hours where the grid frequency exceeds the required limits (49.9-50.1Hz). To improve this situation one alternative is to implement hydropower governing with quicker response time. However, long conduits and oscillatory flow set strict requirements to the hydropower system stability and turbo set governing. This thesis establishes a simulation program based on the structure matrix method for stability analysis of hydropower systems. The method is implemented in a Matlab program to study the oscillatory flow in the frequency domain. Implementation of frictional influence, turbine characteristics, and alternative governing has been given special attention. The program is validated through comparison with measurements and previous analysis at Kongsvinger and Tafjord power plants. The program simulations generally compare well with physical dynamics of the two systems. Further a stability analysis of speed governing at Aldal power plant has been performed. Finally some alternative control systems are discussed.
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Lundström, Niklas. "Dynamic consequences of shape deviations in hydropower generators." Licentiate thesis, Luleå tekniska universitet, Produkt- och produktionsutveckling, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18492.
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Earlier measurements on hydropower generators have indicated the existence of backward whirling motion, and, also relatively large shape deviations in both the rotor and the stator. These non-symmetric geometries produce an attraction force between the rotor and the stator, called unbalanced magnetic pull (UMP). The target of this thesis is to analyse the dynamic consequences of shape deviations in hydropower generators. A mathematical model is developed to describe the shapes of the rotor and stator, and the corresponding UMP is obtained through the law of energy conservation. Theorems about the existence of stable equilibria and whirling motion of the rotor response are proved mathematically for certain cases. The results indicate that different whirling motions, including both backward and forward whirling can occur. Generator dynamics are further investigated by simulating the basin of attraction, giving a measure of the robustness of the attractors. From this, the magnitudes are approximately obtained when the shape deviations become dangerous for the generator. It is concluded which shape deviations that are more dangerous than others. In hydropower generator maintenance the shapes of the rotor and stator are frequently measured. The results from this thesis can be used to evaluate such measurements and explain the existence of complicated whirling motion.<br><p>Godkänd; 2006; 20070109 (haneit)</p>
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Liu, Fuping. "A system dynamics model for hydropower generation planning." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2002. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62782.pdf.
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Thorburn, Karin. "Electric Energy Conversion Systems : Wave Energy and Hydropower." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7081.
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