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1053 Uppsatser om Medium voltage - Sida 13 av 71
Trafikverkets effektstyrningssystem - EFS 132 kV : Bidraget till minskade förluster
The technological legacy from the early electrification of the Swedish railroads has resulted in a power grid with a lower grid frequency than the national power grid from which it is fed. Energy transfer between these power grids with different frequencies requires substations, adapting the grid frequency for the rail road power grid. For this purpose, a feeding power grid has been built, stretching across the country from Boden in the north to Tälle/Häggvik in the south.Power transfer in the Swedish power grid results in voltage angle differences which increase with increasing loads and transfer distance. These voltage angle differences are transferred from the power feeding substations to the rail road power grid, will in some extent cause loss of energy due to unwanted power flows from north to south.To minimize the losses due to this phenomenon, a power management system called EFS 132 kV has been developed and implemented. The system minimizes the unwanted power flows and controls the desired power flow for a good distribution of loads between the power feeding substations.This thesis investigates the extent of the transmission losses avoided due to the EFS 132 kV that coordinates the idling angles to a common reference point.The results indicate that EFS 132 kV affects the power flow, especially between the northern substations through an improved load distribution.
Analys av PWM-mönster i Matlab
One of ABB Power Systems´s business areas is HVDC (High Voltage Direct Current) technology. HVDC is used for transmissions for both short and long distances. One of Power Systems?s products is called HVDC Light. HVDC Light is a relatively new technology for power transmission, but have before only been used for motor drives applications.
VSM och 16 förluster
With background in the rapidly growing need to find solutions for sustainable energy production and the increasing interest for wind power, this report was written. With take-off point from the wind power plant Big Glenn, which has been built in the harbour of Gothenburg, a model of the adjacent power grid has been created in Simulink/SimPowerSystems. Parameters for the power grid and its components has been provided by Göteborg Energi Nät, that has also been the supplier of measurement data of produced power, the power need from loads in the vicinity, voltage levels, current values and also the variation of power factor at the wind power plant.The SimPowerSystems model has been used to perform simulations of power flow in the grid. These simulated values have then been compared to the measured values to verify the functionality of the model. Further, the model has been used to perform simulations of a grid fault, which causes a voltage drop.
Design comparison between HiperLAN/2 and IEEE802.11a services
This paper is a study and comparison between the two Wireless LAN (WLAN) standards HiperLAN/2 and IEEE 802.11a. WLANs are used instead or together with ordinary LANs to increase mobility in for example an office. HiperLAN/2 is an European standard developed by ETSI and the IEEEs standard is American. A WLAN-card consists roughly of a Medium Access Control (MAC), Physichal layer (PHY) and an antenna. The antenna is the same for the different standards.
Does it matter?
Swedish: Det här kandidatarbetet undersöker om karaktärer med icke-normativ sexualitet finns representerade i digitala spel och hur dessa framställs. Arbetet har även fokus på de reaktioner samhället har visat i samband med att spel som behandlar ämnet icke-normativ sexualitet kommit ut på marknaden. Syftet är att uppmärksamma och ge insikt om icke-normativ sexualitet som ämne och hur diskussionen av detta kan leda till en utveckling inom spelmediet. Informationen som användes för att undersöka ämnet och dess reaktioner finns sammanställt under ett forskningsmomentet, vilket sedan utvecklas till flera noveller. Dessa noveller har sedan användes i en undersökning som genomfördes av 11 stycken deltagare.
Kartläggning av begränsande faktorer vid fellokalisering med pulsekometod på mellanspänningskablar
I samband med att mellanspänningsnätet kablifieras ökar också kraven vad gäller fellokalisering. För att hålla avbrottstiderna i nätet korta är effektiv felsökning erforderlig. Detta arbete syftar till att kartlägga och redogöra för begränsande faktorer som finns vid fellokalisering med fokus på pulsekometoden. Uppdraget utförs tillsammans med Vattenfall Eldistribution AB.Det har uppdagats problem gällande fellokalisering på mellanspänningskablar med pulsekometoden. Ett flertal faktorer bidrar till denna problematik.
Dimensionering av hjälptransformator
The aims of the following project has beento make a proposition how to create aspecific kind of transformer. Thefollowing report evaluates the differentimportant variables and contains asuggestion for a possible design. Intheory it's an ordinary transformer that'ssuppose to transform electrical effect toa high voltage line. The design of thetransformer is using an already existingcurrent transformer design and is adjustedto work for it's specific purpose. Theproject also contains the developing of atransformer simulation model that will beused to evaluate and optimize thedimensions of the resulting transformer..
?Knowing what is going on? : -Tågförares upplevelser av ERTMS
The aims of the following project has beento make a proposition how to create aspecific kind of transformer. Thefollowing report evaluates the differentimportant variables and contains asuggestion for a possible design. Intheory it's an ordinary transformer that'ssuppose to transform electrical effect toa high voltage line. The design of thetransformer is using an already existingcurrent transformer design and is adjustedto work for it's specific purpose. Theproject also contains the developing of atransformer simulation model that will beused to evaluate and optimize thedimensions of the resulting transformer..
Does it matter?
Swedish:
Det här kandidatarbetet undersöker om karaktärer med icke-normativ sexualitet
finns representerade i digitala spel och hur dessa framställs. Arbetet har även
fokus på de reaktioner samhället har visat i samband med att spel som behandlar
ämnet icke-normativ sexualitet kommit ut på marknaden. Syftet är att
uppmärksamma och ge insikt om icke-normativ sexualitet som ämne och hur
diskussionen av detta kan leda till en utveckling inom spelmediet.
Informationen som användes för att undersöka ämnet och dess reaktioner finns
sammanställt under ett forskningsmomentet, vilket sedan utvecklas till flera
noveller. Dessa noveller har sedan användes i en undersökning som genomfördes
av 11 stycken deltagare.
English:
This bachelor thesis investigates if characters with non-normative sexuality
are represented in digital games and how these are portrayed.
Konstruktion av current conveyors via makromodellering
A current conveyor is an active building block that can be used to implement most active and passive components. It differs from the operation amplifier in that it uses current instead of voltage. The current conveyor also has significantly higher voltage gain over a broader frequency range. To simplify the construction of analogue circuits and increase the construction efficiency it is desirable to use a top-down methodology. This means that the whole system is partitioned into a hierarchy of subsystems.
Simulering av vindkraftverk och närliggande elnät vid Risholmen i Göteborg i SimPowerSystems
With background in the rapidly growing need to find solutions for sustainable energy production and the increasing interest for wind power, this report was written. With take-off point from the wind power plant Big Glenn, which has been built in the harbour of Gothenburg, a model of the adjacent power grid has been created in Simulink/SimPowerSystems. Parameters for the power grid and its components has been provided by Göteborg Energi Nät, that has also been the supplier of measurement data of produced power, the power need from loads in the vicinity, voltage levels, current values and also the variation of power factor at the wind power plant.The SimPowerSystems model has been used to perform simulations of power flow in the grid. These simulated values have then been compared to the measured values to verify the functionality of the model. Further, the model has been used to perform simulations of a grid fault, which causes a voltage drop.
Sand pits as habitat for ground beetles (Carabidae) : does the area affect species number and composition?
Sand pits are a valuable habitat which can hold many sand living species including several endangered ones. As many sand habitats with exposed sand are declining, sand pits have a potential as a substitute habitat. This study was conducted to see what effect the area of a sand pit has on species number and composition of ground beetles (Coleoptera: Carabidae). Also, the effects of other environmental variables were tested, for example the proportion open sand, vegetation cover, sun exposure and tree cover. The study was conducted in the county of Uppsala in 2008 and included 13 sand pits with areas between 200 and 180,000 m2.
Annonseringsmediet Spotify - Nya möjligheter för mindre företag
The use of streaming media such as Spotify has increased rapidly in recent years. Although the consumption side of Spotify is well established with over 10 million users, the medium might provide new unexploited opportunities as an advertising channel. The purpose of this thesis is to increase knowledge about advertising through streaming media and in particular via Spotify. To contribute to such knowledge we have conducted a case study to investigate how Spotify can be used and serve as an advertising medium for a smaller firm, Hasseludden Yasuragi, so that it may reach its target group. To examine the medial effect, a quantitative as well as a qualitative study was carried out using the ARF Model as a basic framework.
Med kunskap i fokus: En kvalitativ studie av knowledge management på mellanstora svenska managementkonsultföretag
Background: Knowledge management is a concept that is considered of increasing importance in the developing knowledge society. Previous research in the area has to a large extent been based on large multinational companies. Purpose: The thesis aims to clarify how middle-sized Swedish management consultancy companies work with knowledge management. The thesis intends to use existing theories about knowledge management to explain the effect of size and area of operation on management consultancy companies? knowledge management.
"TV-spel är inga konstigheter!": En enkätundersökning om tv-spel på folkbiblioteken
The aim of this bachelor thesis is to investigate the lending of video games at the public libraries in Sweden. The thesis focused around a web survey, which was sent out to all public library directors, as its research material. The results were compared with those found in a master thesis by Olle Berg and Thomas Nyström from 2008. This was done to gain a better understanding of why the libraries provided video games. The other results of the survey were analyzed with a quantitative method.The results indicate that half of the responding libraries provide video games for borrowing.