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945 Uppsatser om Stability calculations - Sida 7 av 63
Konstruktion av turbinmodell för kaplanturbiner
Denna rapport beskriver arbetet med utvecklingen av en ny modell för kaplanturbiner. Utvecklingen bygger på två kopplade differentialekvationer som under arbetets gång anpassats och implementerats i turbinmodellen.Modellen beskriver hur vattenflöde och turbinmoment påverkas av avvikelsen från den optimala kombineringskurvan för vinklarna på turbinens ledskena och löphjul, och är anpassad för ett referensaggregat med tillgängliga provdata. Även övriga enheter i vattenkraftaggregatet modelleras och sätts samman med frekvensregulator och elnät för att simulera aggregatets reglerstabilitet i önätsdrift.Verifieringen av turbinmodellen sker genom försök att återskapa de befintliga verkningsgradskurvorna med hjälp av modellen. Resultatet visar en god följning av de verkliga kurvformerna, dock med något lägre maximal verkningsgrad.Verifieringen av önätmodellen sker genom att prova stabiliteten i nätfrekvens och turbineffekt vid stegpålastningar. Resultatet ger en stabilare reglerstabilitet än i verkligheten, men uppfyller ändå förväntningarna på en fungerande modell.This report describes the development of a new kaplan turbine model.
LAN-Uppgradering
The interest in small-scale electricity in Sweden has increased strongly in recent years. The interest is noticeable both among politicians to increase the share of renewables in the energy mix, and among electricity consumers to partially replace purchased electricity with self-produced. This has resulted in a significant increase of electricity production in low voltage grids in recent years, and the trend appears to continue in the coming years. The majority of the new production plants are solar cells, followed by wind turbines, and it is also in these the greatest efforts are made in this paper.Distributed generation is often seen as something positive since it will contribute to reduced transmission losses and reduced voltage drop in the networks, and that it increases the share of electricity from renewable sources. In cases where the grids are not strong enough, or in other ways not adapted to manage the installed production, power quality may be adversely affected.
Sverigestallet eller uppbundet :
When I got the opportunity to write this examination did I want to write about something
that I both was interest in and also can use in the future. I think it?s going to be difficult
to carry on the milk production with only 28 cows. I wanted to investigate the possibility
to increase the herd of cows. I also wanted to compare this cost with a new cow house
the cows where milked with a robot.
Utvärdering och uppdatering av typkurvor
The purpose of this thesis is to evaluate and update load curves for Fortum Distribution AB. Theload curve method is a tool used to forecast the strain of an electric grid. The method is based oncustomer annual energy consumption, outdoors temperature as well as customer category. Theload curve method was established by Svenska Elverksföreningen at the start of the nineties andfocus was put on standardizing annual energyconsumption, in order to make the method usableacross the nation. Present consumption patterns have changed since the original load curves wereproduced, which leads to a need to update the load curves.The work began with an update of present load curves according to recommendation taken fromanother earlier thesis.
FEM i praktiken : En studie i FEM-Designs användningsområden inom konstruktionsprojektering
This diploma work has been conducted for the consulting company Ramböll inUppsala, Sweden with the purpose to perform a study with the calculation programFEM Design 9.0 made by Strusoft. The aim has been to find out if it is possible to gainadvantage by utilizing more advanced 3D software for design calculations, instead ofthe traditional methods currently used in construction works.The method of approach has been to model an existing warehouse building with theprogram FEM Design, and then compare the results with those attained with FrameAnalysis and hand calculations. These results are then analyzed. An evaluation is maderegarding to what benefits can be achieved using a more advanced 3D-model.The results of the study show that the differences between the methods are not ofany significance with regard to the design of the steel frame. However in morecomplex materials such as reinforced concrete, the differences become more notable.The conclusions drawn by the authors of this study into FEM Design are that theeducation requirements of the program are higher than for simpler programs, whosepurpose are solving predetermined problems.
Kvalitetsegenskaper på en kravspecifikation
The result from Requirements Engineering is a Requirements Specification. Characteristics of a good Requirements Specification are unambiguity, completeness, verifiability, consistency, modifiability, traceability, correctness and ranked for importance and/or stability.This work defines these quality attributes and answers the questions how to reach these attributes and the diffuculties which exist in this area.This work should be read to get an overwiew of the area Requirements Engineering and Requirements Specification..
Transienta strömmar i HVDC-Light
This thesis gives suggestions as to how to design a wooden-based wave-power buoy. The thesiswas carried out at Uppsala University in collaboration with the Division of Electricity and AppliedMechanical Engineering. The product was conceived and developed taking into consideration anumber of requirements put forward by the supervisor, Magnus Rahm. The most importantdemands were that the material used should be able to withstand pressure from the sea withoutbeing damaged and that the production costs should be low.Department of Engineering Sciences, Division of Electricity at Uppsala University was visitedseveral times to discuss issues including the various ideas with the supervisor Magnus Rahm, andwith several people in the department.The work started by studying available literature in order to get background information aboutsuitable methods available for the project and to see how similar projects were carried out. Thereason for this was to get a better understanding of this particular problem and how to solve it.After consulting the supervisor, the group decided to construct four different buoys using fourdifferent materials.
Produktion och dimensionering av träboj i vågkraft
This thesis gives suggestions as to how to design a wooden-based wave-power buoy. The thesiswas carried out at Uppsala University in collaboration with the Division of Electricity and AppliedMechanical Engineering. The product was conceived and developed taking into consideration anumber of requirements put forward by the supervisor, Magnus Rahm. The most importantdemands were that the material used should be able to withstand pressure from the sea withoutbeing damaged and that the production costs should be low.Department of Engineering Sciences, Division of Electricity at Uppsala University was visitedseveral times to discuss issues including the various ideas with the supervisor Magnus Rahm, andwith several people in the department.The work started by studying available literature in order to get background information aboutsuitable methods available for the project and to see how similar projects were carried out. Thereason for this was to get a better understanding of this particular problem and how to solve it.After consulting the supervisor, the group decided to construct four different buoys using fourdifferent materials.
Utvärdering av Capcals förmåga att beräkna framkomlighet
Performance of an intersection affects the total travel time in a traffic network. An intersection with good performance can easily be described by its contribution to lower travel time than in a comparable intersection. The travel time is of importance in the cost calculations when a specific intersection is to be chosen and designed. It is important to be able to make correct and precise performance calculations so that the cost calculations will not be incorrect. For that purpose the software Capcal, which is a traffic model for intersection analysis on performance, is used in Sweden.
Hantering av småskalig elproduktion : Utveckling av modell för dokumentation och elkvalitetsberäkningar
The interest in small-scale electricity in Sweden has increased strongly in recent years. The interest is noticeable both among politicians to increase the share of renewables in the energy mix, and among electricity consumers to partially replace purchased electricity with self-produced. This has resulted in a significant increase of electricity production in low voltage grids in recent years, and the trend appears to continue in the coming years. The majority of the new production plants are solar cells, followed by wind turbines, and it is also in these the greatest efforts are made in this paper.Distributed generation is often seen as something positive since it will contribute to reduced transmission losses and reduced voltage drop in the networks, and that it increases the share of electricity from renewable sources. In cases where the grids are not strong enough, or in other ways not adapted to manage the installed production, power quality may be adversely affected.
Energiförbrukning för putsade, odränerade träregelväggar i fuktigt respektive torrt tillstånd
In recent years, moisture damages have been noticed in rendered, undrained stud walls. The design is built on the principle one-stage tightening which means that there is no air gap in the construction. The damages have occurred when water has permeated through the rendering in leaking connections and fittings for windows, doors, canopies, balconies, terraces and awnings. Behind the plaster carrier, which consists of either polystyrene or rigid mineral wool, plasterboard has often been used as a wind protection barrier. In many cases the wind protection barrier and the underlying wooden studs have been exposed to mould and in some cases even rot.
Jordtäckta hus : Energiberäkningar och kostnadskalkyler på ett jordtäckt hus i Malmö
With rising energy prices and the threat of climate change, energy costs and energy savings havebecome a central and important part in building. Therefore it is interesting to explore different andnon-conventional methods of energy conservation. Building Earth sheltered houses is such a method.Earth provides good insulation and provides the ability to both reduce the total heating needs and toreduce the maximum power demand. The aim of this study was to construct a house in Malmö and seeif Earth sheltered houses can be a cost effective alternative for the construction of sustainable andenergy-efficient houses.Previous studies have shown that Earth sheltered houses have reduced their power requirement with upto 25% and their use of energy with 10%. Numerical calculations in Comsol Multiphysic 4.2, wasperformed on a house with different degrees of earth covering.
Analys av verkningsgrad för en industriell DC-DC omvandlare
This thesis is performed in collaboration with Kraftpowercon AB in Surte, Sweden. Focus has been on to identify the powerlosses in one of Kraftpowercons halfbridge DC-DC converters. First theoretical calculations are made, the calculations is verified with measurements of six different operation modes. In a later stage, methods like soft switching and synchronous rectifying are proposed to increase the efficiency for the converter. To achieve softswitching for the halfbridge, the LLC resonant converter topologies are implemented and examined.
Skalning och brusberäkning av tvåportsadaptorer
The goal of this work is to summarize the calculations for scaling and noise of twoportadaptor. Two different methods has been described and used for the final results..
Möjliga tillämpningar av BIM vid miljöcertifieringsarbete
In the construction industry today there is a significant technological revolution goingon. New methods for automated processes and information management are developedcontinuously. Intense studies are currently taking place to ensure ways and means toembrace the new technology of BIM.At the present, environmental certification systems are considered cumbersome andchallenging. However, the increasing demands of sustainable development in the constructionindustry imply that the environmental certifications will not disappear. ThisMaster Thesis examines the possibilities to apply BIM technology within the field ofenvironmental certifications to streamline the processes.The applications that provide the best opportunities are:- To use BIM to be able to, during the design stage, dynamically evaluate the resultor score a certain building will achieve.- To avoid unnecessary work through collection of data for calculations directlyfrom a BIM-model.- To be able to automate certain time consuming calculations that are currentlyperformed manually.- To automatically examine the completed model to ensure that the demands arefulfilled.The possibilities to use BIM within these areas are however limited by the technologyitself.