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10901 Uppsatser om Power system stability - Sida 29 av 727
Effekter av EDI
Background: It has been shown that EDI can yield positive effects within companies. Which effects are possible for a company to direct assign to the introduction of EDI and is it possible to estimate the total effect.Purpose: The purpose of this study is to estimate and analyze the effects of using EDI in electronic business. We also want to contribute with a model for measure and estimate the effects of EDI.Accomplishment: We have studied literature concering EDI and realized a preliminary studie in form of interviews with experts to establish deeper knowledge of EDI. We have also tried to estimate the effects obtained in companies in three different businesses, power, government and transport industry.Result: To obtain as good effects as possible it is important that the co- oporation is built on trust and engagement. Before implementing the EDI-system a thorough overhaul of the processes in the company should be done, involving both the top managers and the staff.
Nollföljdsmodellering av transformator-Beräkningar av följdproblem vid ökad kablifiering på mellanspänningsnivå
Historically transformers with system earth equipment have been modeled as open circuits in zero sequence. This approximation has been satisfying, but lately it has been discovered that equipment on one side of the transformer have responded to faults that occurred at the other side. Most of these problems took place when the majority of the system on the secondary side of the transformer contained cables. These findings have led to questioning whether or not the former model of the transformer in zero sequence is correct. This report investigates if it is necessary to represent the transformer in zero sequence in another way than it is usually done today.
Investeringsbeslut för småskalig vindkraft : en fallstudie
Wind power is one of the sources of renewable energy which has to be developed further in order to lessen our dependence on non renewable sources of energy. It's mainly oil and coal which have to be replaced by green energy. Wind power is already established in many countries, for example Germany, The United States of America and Denmark but it has to be continually developed and expanded to meet the needs of the growing energy consumption in the world. During the last few years many types of small wind turbines have appeared on the market. These small wind turbines are an alternative to the big wind turbines or power generators which demand huge sums of investment money.A new target group can now buy the small wind turbines in order to cover their own usage of electricity.
Hur enkel- & dubbelportsturbin i kombination med två olika avgassamlare påverkar gasväxlingsprestanda på en Scania V8
The exhaust arrangement on a Scania V8 consists of one manifold at each bank connected to a twin entry turbine (8-2-2). A study in GT-Power has shown improved performance and reduced cylinder to cylinder variations using two manifolds at each bank in combination with a single entry turbine (8-4-1). This thesis work analyses the difference in performance shown in simulation and verify it by engine test.The initial work was focused on simulation in GT-Power. Investigating how exhaust manifold volume and pulses effects the turbine efficiency and the mean effective pressure during the gas exchange. To verify GT-Power simulations four engine tests with different exhaust arrangement have been made.The results from GT-Power simulation indicate that a larger exhaust volume improve the turbine efficiency.
Analys av mätdata från nätstationer
Fortum has in a pilot project installed metering equipment with wireless communication in secondary substations in Stockholm. So far, the collected data are used only in specific projects.This master thesis was carried out at Fortum Distribution AB in Stockholm during 2013. The purpose of this study is to simplify and enhance the use of data in for example network planning process, by giving suggestions on how data can be managed and giving examples of analyzes that collected data can be used for.The electricity meter which Fortum has installed is a EDMI-Mk10A which is set to measure max/average/min values with a one hour time resolution of the following parameters: voltage (per phase), current (per phase) andactive power and active and reactive energy.In order to analyze the collected data an analysis tool is required. During this thesis two customized tools in Microsoft Excel have been developed, one for sorting data and one for analyzing.One aim of the thesis is to show examples of what collected measurement data can be used for. This work shows an example of analysis of active power, power factor, voltage, occurrence of interrupts and the relationship between outdoor temperature and power.This master thesis has among others resulted in the following advice: Expand the number of secondary substations with measuring equipment.
Webbaserat ordersystem samt CRM.
The author of this report has created a Web-based invoice system and CRM at therequest of the company Webhouse.se. The purpose of the System is to makeeveryday tasks in the company easier. The system also needed to prevent mistakesand errors by managing orders and invoices.The system has been created with the company?s requests in focus. During thedevelopment of the system information security and interaction design have beenimportant aspects that have been taken into consideration.The system has been created using techniques such as PHP and MYSQL.
Från snopp till kropp : En c-uppsats utformad inom sex och samlevnad
Detta är endast en del av ett stort arbete, på grund av omständigheterna (till exempel möjligheten att publicera en power point) har vi varit tvungna att begränsa vår publikation till lärarhandledningen. Det finns också en elevutgåva, power point-presentation samt ett prov som inte publiceras. För att ta del av dessa krävs möjlighet att komma åt Biologi C för lärares kurswebb Vt-2008 på Södertörns högskolas intranät. .
Svininfluensan : en kritisk diskursanalys av medias rapportering
Media has the power to influences society. Some call them the third power of a state. Through amongst others, the agenda setting theory and the framing theory, this report seeks to understand how media describes the swine influenza and how it uses its power to influence people to vaccinate. As this report will show, there is no doubt that media has had an impact on the Swedish population of which 60 per cent followed through with the vaccination. Media used an information discourse and attempted to present its articles in an impartial manner and used governmental authorities and experts to support its arguments.
USA och Indien: ett växande strategiskt partnerskap och makt som balanserar
The study focus on the development of the bilateral relationship between India and the United States and the Next Step in Strategic Partnership (NSSP) from 2004 and the change in U.S. approach to India's neuclear program. With the rise of China to potential great power status I argue that the cooporation between the two is an act to balance the Chinese influence and to prevent future rivalry and a Chinese dominance of the East Asia. For the study I have used concepts and theorys from the realist tradition, in particular theorys of Balance of power and alliance forming..
Det var livet att slåss, att alltid vara en krigare : En studie om unga i vit makt
We have studied the process of recruiting young people to the white power movement. With the help of theoretical concepts as Outsiders and Stigma, we have elaborated the purpose of the study. The focus of the study lays in finding out which elements contributes to adolescence seeking membership in white power, and furthermore what white power organizations offers young people, to attract them to recruitment. We also want to find out if it possibly lays a desire for communion, behind adolescences decision to join these movements, and also how the communion manitains within the group? To expand our knowledge in the field of White Power, we have taken note of a body of literature that deals with the current topic, and previous research that treats questions about subculture, community and recruitment.
Framtidens elbilar utmanar nutidens elnät : Påverkan av ett ökat antal elbilar på ett halländskt elnät
The challenges facing low voltage grids are rising as an increasing number of domestic houses transition from fossil fueled heating to electricity based heating. Several environmental goals and visions have the same transition from fossil based power to electricity based power in mind for the transportation sector. One of the most important tools for this transformation is widely regarded to be the electric vehicle. With the demands of the electric vehicle pressuring the power grid, several questions arise regarding the growth of the electric vehicle market and what repercussions it may have on the grid. This paper focuses on a typical low voltage grid in southern Sweden and what effects a growing electric vehicle market may have on it. Through computer-assisted simulations based on several future scenarios regarding the EV market, this paper finds that few modifications and reinforcements are needed on this particular grid within the next 10 to 15 years.
Mjukvaruplattform för riggstyrning
Today the competition in the automobile industry is getting all tougher. The technology behind cars becomes more advanced. To get ahead of competitors car companies has to look into new areas of innovation.One important area is vehicle safety. Bigger companies have come so far in vehicle safety that difference between cars more depends on the car type (size) than the technology behind it.There is one area where vehicle safety that still has great opportunities for improvement, which is in active safety. The term active safety states that the car has the ability to identify treats and automatically respond to the treats.
Implementering av mjukvarubaserat PLC-system för reglering av magnetiseringen av en synkrongenerator
In order to reduce the price for, and improve the performance of automatic control systems for magnetization of synchronus generators, the possibilities of using a PC based software PLC system, Programmable Logic Controller, has been investigated. The result is a system based on the CoDeSys software PLC with runtime environment from 3S-Software, communicating with external units via Modbus fieldbus. System price is reduced from ?5000 to ?2000 and system processing speed is reduced from 10 ms for a Siemens S7 PLC to 4 ms with the CoDeSys PLC system though unsolved problems with runtime seizure caused by improper settings in the PC BIOS..
Brukarperspektiv på vad som är hjälpande i relationen till professionella : En kunskapsöversikt
The relationship to professionals has proved to be a helping factor for personswith severe mental illness, but it is also a relationship characterised by anunbalanced power relation. The aim of this study was to compile and analyze theknowledge of what persons with severe mental illness themselves consider to behelping in the relationship to professionals, and to specifically analyse this from apower perspective. The analysis was conducted using Foucault?s ideas of powerand knowledge, and an empowerment perspective. The method used was anarrative review.
Inventering av värmelager för kraftvärmesystem
When a combined heat and power plant produces heat and power it often faces a deficit of heat load during the summer or other periods of time. This heat is often unnecessarily cooled away or the power production has to be reduced or shut off. If it is possible to store heat from periods with low heat demand to periods with high heat demand one can get many benefits. Among these benefits are: increased power production, decreased operation with partial load, uniformly distributed load.To be able to store heat in situations like this long-term thermal heat storages are needed. In this thesis five different types of stores are presented: rock cavern storage, tank storage, pit water storage, borehole storage and aquifer storage.