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10901 Uppsatser om Power system stability - Sida 7 av 727

Alice Springs drivet av solenergi - En jämförelse mellan solceller och Stirlingsystem

In the middle of Australia there is a city called Alice Springs. The city has one of the highest amounts of daily sunshine hours and sun irradiation in the world. The Australian Government runs a project called Solar Cities, and Alice Springs is one of the participators. The main part of the goal with the Solar Cities project is to increase the amount of electricity generated by solar power and by doing that lower the impact on the environment. This thesis examines the possibilities for construction of a large scale solar power plant in Alice Springs. This is done to determine the potential of creating a more sustainable energy system in the city.

Alternativa dagvattenlösningar för nyexploateringsområden med avseende på substansflöden

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.

Religion och vetenskap i läromedelsböcker : En studie av vilka bilder av religion och vetenskap som förmedlas i läromedelsböcker i religionskunskap för gymnasieskolan

The purpose of this thesis is to identify power structures and instruments of power within the Jehovah?s witnesses and investigate how they affect the baptized youths baptized within the organization. The material consists of qualitative in-depth interviews and is analyzed with Foucault's theories of power. The results show that the participants have a very strict relationship to the rules of the congregation and also that they take great care in observing these rules carefully. It becomes evident that young members are exposed to disciplinary measures from the organization.

Operation Rolling Thunder

This paper provides an explanation of the concepts John A. Warden III describes regarding the use of air power and if this theory can be found, within the confines of an unconventional war. The U.S. ability to air power is overwhelming, however the right kind of warfare can force this great power to abandon their military and political objectives by exhausting its resources over time as it becomes increasingly costly, both economically, politically and morally, to wage war. The research deals with operation Rolling Thunder and John A.

"Allt man gör ska ära Gud" : En studie av organisationen Jehovas vittnens maktstrukturers och maktinstruments påverkan på unga Jehovas vittnen i Sverige

The purpose of this thesis is to identify power structures and instruments of power within the Jehovah?s witnesses and investigate how they affect the baptized youths baptized within the organization. The material consists of qualitative in-depth interviews and is analyzed with Foucault's theories of power. The results show that the participants have a very strict relationship to the rules of the congregation and also that they take great care in observing these rules carefully. It becomes evident that young members are exposed to disciplinary measures from the organization.

Modellbaserad drivlinereglering

A cars powertrain consists of everything that is needed for its propulsion. The components in the driveline that transfer the power from the engine to the driven wheels are not absolutely stiff, hence they will wind up due to the torque and act as torsion springs. If you suddenly demand a bigger torque by stepping on the accelerator pedal, a so called tip in manoeuvre, and that torque is acquired from the engine as quickly as possible, the driveline will not be able to transfer that fast torque change due to its weakness and as a result it will start to oscillate. These oscillations will be transferred to the driven wheels and make the car to accelerate jerkily which will be experienced as uncomfortable by the passengers. Furthermore, there is a backlash in the driveline that will make the weakness in the driveline even more excited than it should have been if the backlash did not existed.To avoid too big problems with these oscillations there is a control system that controls the demanded torque.

Energi - och ekonomipotential för solceller i Hållbara Järva

One of the city of Stockholm?s main objectives is to have a society completely free from fossil fuels. To achieve this, several investments regarding improvements in energy efficiency and renewable energy are currently being planned or implemented. One of these investments is a project called Hallbara Jarva which is located in the suburbs of Stockholm. The purpose of this thesis is to examine the prospects of an investment in photovoltaic cells from an energy-saving and economical point of view. The analysis is limited to three buildings within Hallbara Jarva and is intended for the property owner.  Solar energy is a type of renewable energy source and is commonly divided into solar heating and solar power.

Test-retest reliabiliteten i balanstesterna Unilateral stance, Limits of stability och Rhythmic weight shift

Människans balanssystem kan beskrivas utifrån tre delkomponenter, det vestibulära, det visuella och det somatosensoriska systemet. En rad olika skador och sjukdomar som påverkar dessa system stör därmed också balansen. Balansstörningar kan verifieras med hjälp av funktionella tester eller teknisk utrustning. Då teknisk utrustning används är det vanligt att instrument utnyttjas med kraftplattor i syfte att mäta det posturala svajet hos patienterna. Vid balansutvärdering är det viktigt att de instrument som används är validitets och reliabilitetstestade.

Makt i klassrummet : En maktanalys av relationen mellan lärare och elev

This essay is about power in the classroom. It is about the power dimension of the student-teacher relationships that arise in that space. The overall aim has been to investigate which categories are fruitful in a power analysis of these relationships. My aim has therefore been to develop power categories and to use them to identify and to categorise cases of power interaction that take place between those particular actors in that particular setting.In order to gather material for my study I have both read literature that approaches the study of the student-teacher relationships from a power perspective and done a series of observations in a high school.My theoretical frame comprises a concept of power and a series of power categories. These categories include strength, authority, inducement, coercion, violence, resistance as well as to possess power, to have power, to exert power, the scope of power and the base of power.

Distriktssköterskans erfarenhet av interventioner riktat mot att förebygga viktnedgång hos personer med Alzheimers sjukdom : En intervjustudie

The purpose of this thesis is to identify power structures and instruments of power within the Jehovah?s witnesses and investigate how they affect the baptized youths baptized within the organization. The material consists of qualitative in-depth interviews and is analyzed with Foucault's theories of power. The results show that the participants have a very strict relationship to the rules of the congregation and also that they take great care in observing these rules carefully. It becomes evident that young members are exposed to disciplinary measures from the organization.

Hjälpkraftsystem med två lågspänningsnivåer

Because of increasing demand of power on Malmbanan the capacity of the existing wires which supply the trains must be increased. This increases the stress on the existing poles and for this reason the system for supplying the loads along the railway is to be removed from the poles and be replaced by some other system. This thesis is a study on a two-level low voltage (1 kV and 0.4 kV) electrical system with the aim to investigate if it can be an alternative to the system used today taking into account the voltages, fault currents and costs.In this thesis the following tasks have been performed:? Gathering of data? Description of basic theory? Loadow and fault current calculations of the system with MATLAB? Life Cycle Cost estimate of the system? Analysis and conclusions from the resultsThe results show that the new system can be an alternative to replace today's system. The simulations and calculations show that the voltage drop is at an acceptable level and that the fault currents are large enough to supply a safe disconnection if a fault occurs at the far end of the system..

Att Spela Roll - Folkrepubliken Kina som Supermakt

Since the abrupt ending of the Cold Wars the international system of politics has been dominated by the unipolar United States. Leading scholars within structural realism sees this stage as just a temporary condition for various reasons. They also target China as aspirant to embody the role of a balancer against USA and pole in a bi- or multipolar system. Some even argue they are destined for superpower.With the help of realisms definition of power I estimate U.S., China's and India's capabilities and judge their potential superpower. I then go on to connect structural realism and role theory to estimate their different statuses in the system.

Design och tillverkning av en stereoanläggning med aktivt delningsfilter

This thesis is the result of the author?s interest in music and electronics, namely the design and manufacturing of a stereo sound system with an active crossover. In short it can be stated that an active crossover has many advantages over its traditional passive counterpart. The active design naturally results in a more complex system comprised of a multiple number of components. This report deals with the theoretical aspects of preamplifiers, crossovers and power amplifiers as well as power supply and control.

Effekten av höghöjdsvistelse på anaerob arbetsförmåga

Syftet med denna studie var att undersöka om vistelse på hög höjd påverkar den anaeroba arbetsförmågan. Sex aktiva universitetsstudenter, fyra män och två kvinnor, deltog frivilligt i studien. Expeditionen till Nepal varade i 40 dagar och under den perioden sov och vandrade försökspersonerna mellan 1400 och 5100 meter över havet. Före och efter expeditionen genomförde försökspersonerna ett anaerobt wingatetest där peak power, average power, minimum power and power drop uppmättes. Resultatet visade en signifikant sänkning av average power efter den genomförda expeditionen på hög höjd, med ett medelvärde på 8.44 ± 0,84 w/kg före expeditionen och 7.81 ± 0,87 w/kg efter expeditionen.

Åsktransienter och överspänningar : En spänningsfylld simulering av elkraftsystemet vid Forsmark 3

A power system will inevitably be subjected to transient overvoltages, most often produced by switching operations and lightning strikes. These transient overvoltages may harm sensitive equipment without sufficient protection, but it is not an easy task to predict what transients may occur or how they affect the system. A fault occurred in a low voltage system at Forsmark 2012 and overvoltages from lightning were concluded as the probable cause. The three aims with this thesis are to develop and test a model of the power system at Forsmark 3, analyse the transient behaviour of the system when subjected to lightning surges and identify critical parameters, and lastly to provide a tool for investigating the protection of the system. The modelling and simulations were performed in the freely available simulation program LT Spice.

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