Sökresultat:
314 Uppsatser om Voltage disturbances - Sida 17 av 21
Dokumentation av en experimentell biogasanläggning
This thesis is focused on identifying and documenting all electrical equipment, such as devices, power lines / cables, and connectors in the facility and also on presenting a brief technical description and information of the systems around the reactors. Furthermore there will be a brief description of LabVIEW - which is a graphical programming language- and which devices / elements are programmed. For further notification, I am not responsible for the programming of the devices in LabVIEW which I have only used as a tool in my work. The plant for production of biogas consists of four reactors of which the third reactor (Lakbädden) is connected to another reactor (UASB) where they cooperate with each other. The reactors are used for producing biogas in the form of methane gas.The reactors I and II are connected to, various electrical devices as, flow meters, temperature sensors, frequency converter and more.
Analys av mellanspänningsnätet i centrala delar av Västerås stad
The dependency of continuous electricity supply is high in the Swedish society today, at the same time no one is willing to pay for a too costly or over dimensioned power distribution system. The owners of the distribution systems are the ones responsible for this balance act of maintaining a high quality of electricity delivery to customers at a reasonable cost.In this master thesis a limited part of the primary distribution system (10 kV), owned by Mälarenergi Elnät AB and located in the city centre of Västerås, was chosen for a deeper analysis of its reliability. Its ability to handle outages of system components (N-1 and N-2 contingency analysis) was investigated to find out potential weak spots and parts of the grid that showed signs of being overdimensioned.The results of the performed simulations showed that in 74 % of the studied N-1 contingencies cases, consisting of outages of a bus bar in a distribution substation, the system could handle this without causing outages in other parts of the grid. For the N-2 contingencies 61 % passed the test. It was also found that one of the two included high voltage substations could alone supply the investigated part of the grid.
Lärsituationens komplexitet för elever som upplever svårigheter i matematik : Rutiga Familjen i en ny lärmiljö
The Squares Family is a game developed as a learning aid in mathematics. With its graphical representation of the decimal system, the four basic arithmetic operations and positive and negative numbers together with a learning agent as pedagogical approach, the game?s primary purpose is to motivate students in their learning of mathematics. Although the game is strictly based on mathematical rules it attempts to encourage students to play and work with math without experiencing it as mathematics as this is initially not obvious. The game being internationally tested on normal performing students, this project introduced the game to six Swedish students who experience low motivation for and/or difficulties in mathematics.
UNDERSÖKNING AV FEL OCHSTÖRNINGAR SOM PÅVERKARBYGGPROJEKT
Detta arbete kommer att behandla olika typer av fel och störningar som påverkar ettbyggprojekt. Byggprocessen i sig involverar många aktörer som måste samarbeta för att nåuppsatta mål och därmed hålla sluttiden. Från det att byggherren har tagit ett beslut att startaett byggprojekt till att byggprojektet nått sin slutliga fas ställs det krav på alla aktörer. Ibyggprojektets tre olika skeden ? program, projektering och produktion ? uppstår olika typerav fel och störningar som påverkar byggprojektet negativt.
Avbrottsfri Kraft med användning av ultrakondensatorer
The supply of uninterruptible power can be applied to many areas wherecontinuous operation is highly prioritized.The application of uninterruptible power for motor operation is facilitatedusing a frequency converter. Direct current operated frequency converters canbe applied directly to the power reserve which removes the need for additionalpower-converting.Batteries have long constituted the power reserve but advancements inthe development of ultracapacitors have created a viable substitution. Ultra-capacitors have high energy storing capabilities and can be applied to highpower applications.Maxwell is a leading manufacturing company of ultracapacitors and pro-vide different modules with built-in solutions for voltage balancing. Unevenvoltages between series-connected capacitors is a phenomenon caused by vary-ing capacitance. A configuration containing Maxwell?s 56V module is createdand constitutes the power reserve in the simulations.The discharge simulation shows a significant current that could damagethe system.
Säkerhetsanalys av brandbekämpning i kritiska utrymmen på Forsmark 1
In order to maintain a high safety level at a nuclear power plant it is important not only to measure the reliability of the components and systems of the plant, but also to investigate how the plant responds to human actions. One of the most hazardous situations in managing a power plant is fire occurring in critical areas. This study concerns the prospect of the local fire brigade to suppress a fire that has started in one of the most critical rooms for maintaining high reactor safety. The model created gives an indication on the possibilities of succeeding in suppressing a fire. In order to get a more reliable fire fighting the following advice are given:- Let the fire brigade go rounds in the plant together with the personnel, during which recommended fire suppressing methods are determined to avoid long preparation time in an actual situation.- Prepare rooms with two subsystems to make them partly with no voltage.- Give the fire brigade better feedback from actual events on nuclear power plants.- Education and training in suppressing fires in electrical equipment.The probabilistic safety assessment strives to be as realistic as possible.
Krisberedskap i grundskolan : perspektiv på krishantering
A crisis is something that can happen to all of us in an unexpected situation, and the school should be prepared in a way that is the best way to handle a situation with a wide foundation through a crisis plan. On a well-defined way, you should have a developed and relevant emergency plan. Defining the word crisis can be difficult, it is an individual interpretation, and to get found out what the word stands for and it have to be discussed. The two selected schools that I have chosen to interview have discussed the understanding of the word crisis in able to get what the word means for them. The two selected schools have come to the conclusion that a crisis is something that creates disturbances for people or a person concerned to the everyday way of living.
Membranbioreaktorteknik- en framtida lösning på Lundåkraverket? : Membrane bioreactors- A future solution at Lundåkra wastewater treatment plant?
Membrane bioreactors (MBR) combined with biological phosphorous treatment (Bio-P) has been investigated if that could be an alternative to the future expansion with conventional active sludge treatment at Lundåkra wastewater treatment plant (WWTP) in the proximity of Landskrona, Sweden.The results showed that the surface demand in the biological treatment will be reduced with 67% with the MBR-alternative compared to a conventional activated sludge process. The nutrient removal in the MBR-solution was decreased or unchanged for nitrogen-, phosphorous- and organic parameters. However, the energy demand will increase with an estimated cost of approximately 1 million SEK annually. Moreover, the extra chemical consumption is estimated to cost 370 000 SEK annually.The disturbances caused by filamentous bacteria such as sludge dispersal could be resolved with MBR-technology because the membranes are not affected by these organisms. The Bio-P process combined with MBR-technology works if the wastewater recirculates from the membranes to an aerobic zone.In the proposal, there will be a new pre-treatment step, for instance hole screens.
Kaninen som produktionsdjur
The purpose of this report was to obtain an overview of rabbit meat production in the world, in terms of breeding and feeding. It examines how different feed components contribute to the health of the rabbit as well as the quality of the carcass, and the breeding strategies that are most common in the major producing countries. The production of rabbit meat in Sweden is at present not very large, but it is gaining ground, and that is why this paper mainly deals with the rabbit production abroad. This report also examines the disease Rabbit Viral Haermorrhagic Disease (RVHD) in Sweden, where this disease can cause big problems.
The rabbit (Oryctolagus cuniculus) is very special, both in its reproduction and digestion. There is no specific mating season and the digestive tract is designed to digest forage efficiently.
Spänningsfall i 200 V 400 Hz system
Målet med examensarbetet har varit att ta fram teoretiskt underlag och en beräkningsmodell. Detta ska beskriva hur kabeltyp, kabellängd, kabelarea samt effektfaktor påverkar spänningsfallet över ett 400 Hz ledningssystem.Mätningar har utförts på två olika kablar som används i det aktuella systemet. En av kablarna var symmetriskt uppbyggd med 7 ledare, där respektive fas bestod av två ledare förskjutna 180° från varandra runt nolledaren. För att åstadkomma 115/200V 400 Hz, användes en 90 kVA frekvensomformare. Belastningen som användes var en resistiv, induktiv samt en kapacitiv belastning.
Numerisk simulering av jordtryck mot rörbro ? Med tillämpning av programmet PLAXIS
This thesis deals with numerical simulation of earth pressure against tubular bridges in the software Plaxis. Plaxis is a FEM (Finite Element Method) software based on numerical calculations for which approximate solutions are developed through an iterative process. The program is specifically designed for soil and rock mechanical tests, such as voltage and deformation calculations in soil.The Royal Institute of Technology conducted in 2005, field tests on tubular bridges of corrugated steel, which was part of Ersa Bayoglu Fleners PhD (Bayoglu Flener, 2009). She studied how two different tubular bridges deformed during installation and filling. Tests and measurements were made during filling.
Jämförelse mellan ?Auditory Brainstem Response (ABR) och ?Auditory Steady State Response? (ASSR) för att uppskatta hörtrösklar på barn i narkos. Kan testtiden minska om 500 Hz utesluts vid ASSR-mätning?
ObjectiveThe objective of this study was to investigate the clinical application to use ASSR in anesthetized childrenDesignOne main ambition of the investigation was to compare hearing threshold using ABR with estimated hearing threshold using ASSR. Another aim was to examine if the duration of an ASSR measurement could be reduced by only using the frequencies 1, 2 and 4 kHz and exclude the frequency 0.5 kHz. This is a retrospective study using electrophysiological measurement from a database.ResultResults showed a high correlation between hearing threshold using ABR and estimated thresholds using ASSR, with the frequency 0.5 kHz showing a slightly lower correlation. Result also showed that the test duration was increased when using all test frequencies in ASSR-measurement compared to when 0.5kHz was excluded. ConclusionThe study showed a high correlation when comparing hearing threshold using ABR and ASSR.
Fenylbutazon - tillåta vid tävling?
Phenylbutazone has been discussed in the world of the equestrian sport several times and different countries have diverse opinions on its use in competitions. The progressive list that permits phenylbutazone with plasma levels up to 8 µg/ml was presented at the FEI General Assembly in November 2009. The list was voted to be accepted, but later several countries realized the consequences and after protests the list was rejected and is going to be discussed again at the FEI General Assembly 2010. In this literature study I have studied the relationship between the concentrations of phenylbutazone in plasma and the effects on lameness. The purpose was to establish whether the limit of 8 µg/ml phenylbutazone in plasma affects the equestrian sport.
Brown bear (Ursus arctos) den site concealment in relation to human activity in Scandinavia
As a hibernating species, the brown bear spend most of the winter months in a den as astrategy to avoid unfavorable conditions. The denning period is a vulnerable time for bears,making them unable to flee disturbances without losing valuable amounts of energy. Brownbears' wariness of humans and avoidance of anthropogenic disturbance often steer denningbears away from human infrastructure, and bears thereby avoid possible disturbance and itsassociated energetic costs. This study was carried out to test the hypothesis that bearsdenning closer to infrastructure select more covered den sites to compensate for the closedistance. Dens from 32 individuals were visited and analyzed in terms of sighting distance(a measurement for den horizontal cover) and habitat ruggedness, in relation to distances toinfrastructure.
Termisk Vattenpump
This degree project aims at developing a concept for how to use solar energy to pump up water. The target audience is people living in areas where the functioning of the electricity and water network is absent. In these areas, the hand-powered water pump is the most common technology. The degree project's goal is to find an economically viable alternative to the time consuming hand-powered water pumps. The power comes from solar energy.