Sök:

Sökresultat:

3488 Uppsatser om Power distribution - Sida 1 av 233

Metoder för kartläggning och analys av nätförluster i lågspänningsnät

An important process for grid companies in order to reduce power losses in electricity distribution grids is to figure out where and how they appear. This report describes the factors that cause power losses in low voltage distribution grids and methods for how they could be measured and analyzed. Measurement data for consumed and injected energy were collected for twelve low voltage distribution grids owned by Gävle Energi AB in order to analyze the size of the power losses and how the measurement uncertainty affects the collected data. Then models of three of the grids were created in MATLAB in order to analyze the data and the power losses were calculated to be compared to the collected data. Curve fitting were also used as a method in order to analyze the power losses from collected data.The results show that the losses in the studied grids are low.

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.

Vem får höras? : En undersökning av lokalpress kring makt och kön i fyra Landsortstidningar

2 (45)AbstractAuthors: Gunnel Forssell Ehrlich & Alexandra WinbergTitle: Gender in local press ? a quantitative study of four local newspapers Level: BA Thesis in Media and Communication StudiesLocation: Linnaeus UniversityLanguage: SwedishNumber of pages: 50The report shows a quantitative study of balance in gender and position of power in the local press. The study aimed to shed light on the distribution of space in the newspaper between men and women, those within power and those without in Swedish local press. The study was conducted with four newspapers, during a month of time with local editorial news material. In our study, we have assumed Lippmann?s and Strömbäck?s theories of pseudo-reality and distribution of gender and position of power in Sahlstrand and Jarlbro.

Representativa testnät försvenska eldistributionsnät

This project was started within the Market-Design programme of Elforsk, with the aim of developing representative test systems of Swedish distribution networks. Using such test systems as a basis for reliability and customer interruption cost calculations makes it feasible to analyse the network tariff regulation of Swedish power  istribution companies. In particular, it enables studies of the incentives for companies to invest in system reliability. Until now, the available test systems are either not representative of Swedish conditions, or too small in scale and limited in function.Within this project we have created two test systems. In order to represent the diversity of actual Swedish distribution networks, we have created one test system for urban environments and another for rural environments.

Faktorer som påverkar vindkraftsutbyggnaden

Wind power is expanding rapidly in Sweden. Increasing amounts of wind power sets higher requirements on balancing power and grid expansions and would affect the whole Swedish electricity system. The aim of this report is to examine the factors affecting the wind power expansion in Sweden. How many wind power plants projects will obtain building permissions and what costs and revenues can be expected? How much balancing power will be required and does a changing geographical distribution of the wind power plants reduce the need of balancing power?A survey of the county board?s official applications has been made and out of all the applications, corresponding to 80 TWh produced per year, about half of the applications are expected to obtain a permit with a major portion of them located in the north of Sweden.Especially older wind power plants, deriving revenue from Nord pool, find themselves today in a complicated financial situation.

vindkraftens påverkan på elkvaliten

This thesis concerns how the power quality in the grid is affected by the connection of wind power plants. As things are at present, Fortum Distribution AB has a number of wind turbines and wind parks connected to the own grid. As the pressure on building and connecting additional wind power is increasing, so is also the interest of how the already existing wind power generation affects the power quality in the nearby distribution grids. The study is performed by direction of Fortum Distribution AB and is limited to the 10 kV/40 kV-grid in Bohuslän, Sweden. The methods for calculation of power quality are compared to the results of a number of measurements.

Överföring av och beräkning med timmätta värden ? från MT2000 till Xpower

New technology makes it possible to remotely measure all consumers in a power network onan hourly basis and store the values in a database.This thesis work describes the conversion process between automatic meter reading systemMActor and calculation software Xpower.Then the possible differences between calculations of power networks using load curves incombination with a yearly estimate of consumption and calculations using hourly measuredvalues is examined.The result of the comparison shows that, for the power network under inspection, nosignificant difference could be noticed. This does not mean that calculations using hourlymeasured values would be unnecessary. I believe that in a near future calculations using hourmeasurements will be the primary choice for many power companies to whom technology isavailable.Also some basic calculations of fundamental power network parameters, such as power factorand loses, are presented using hourly measured distribution transformers in combinations withits hourly measured loads.The report is written in Swedish.

Design och framtagande av mätanordning för ström och effek på trefas ledare : Josi Periferi strömmeter

The assignment is issued by Scania Maintence AB seeking a new approach to detect power changes in their industrial processes. The work has taken place at Ångströmslaboratoriet and tests have been performed at Scania AB Södertälje.Today?s society consumes enormous amount of energy. In both economically and environmental view, it is important that the processes are effective, with high power factor. There are many ways to measure power in the industry, what they all have in common is that the installation is advanced, requires time and planning.

Magnetfält alstrade kring nätstationer i samband med lokaldistribution av elkraft : Magnetic fields generated by electrical substations during distribution of electric power

Abstract: This report covers primarily the work of documenting electromagnetic fields generated by one of the later parts in the electrical Power distribution chain: The electrical substation, wherein 10 kV is transformed to 400 V for use by private consumers. Thus it is one of the most widespread and frequently occurring parts in the Swedish power grid and of particular interest, as electrical substations are found everywhere in populated areas, often in close vicinity to people and animals.The report deals with a number of formulated questions and/or hypothesis? stated at the onset of the work undertaken, theory that is relevant for the topics the report covers, the details of the field work undertaken and the following analysis of the readings, which in term provide answers for the questions stated in the beginning. It also covers what is the currently known short term and long term risks associated with electromagnetic fields in the power frequent spectrum and of varying intensity in the vicinity of humans.The analysis also provides recommendations and identifies several points to carefully consider when planning for new installations or replacements of some parts of existing installations.For enhanced reading comprehension there is, aside from sections with pictures and attached explanatory texts and templates, several graphs, one-line diagram and maps of the power grid among the appendixes to the rapport..

Utveckling och tillämpning av modeller förkvantifiering av de ekonomiska konsekvensernaav ökad förbrukningsflexibilitet inom eldistribution

One step towards a more sustainable energy system is to create a more flexible electrical grid, where increased demand response among electricity consumers can play an important role. A distribution grid owner can encourage their customers to use electricity more evenly distributed during the day by introducing different types of grid fees such as time-differentiated power tariffs. In this master thesis, the theoretical economic impact of a flattened load profile for a distribution grid owner is investigated. Different factors that impact the distribution grid owner?s economy are identified and two are chosen to be quantified; losses in the grid and the fee to the feeding grid.

Risken för översvämningar vid de svenska kärnkraftverken : en statistisk och historisk extremvärdesanalys

This thesis investigates the overall risks of flooding over the Design Basis Flooding Level (DBFL) at the Swedish nuclear power plants (Oskarshamn, Ringhals and Forsmark), using statistical data and methods, but also considers historical events which might affect the overall risk of flooding at the specified sites.Considering the nuclear accident which happened in Fukushima in conjuction with the earthquake and tsunami which struck eastern Japan on 11 March 2011, operators and licensors of nuclear power plants all over the world conducted reviews and investigations on the overall risks posed to the plants from external events. One important such event is extreme water level.One part of the thesis includes an extreme value analysis (using Generalized Extreme Value distribution and Generalized Pareto distribution) of water level data from SMHI (Sweden's Meteorological and Hydrological Institute) measured at stations close to the Swedish nuclear power plants. The results of the statistical studies indicate that considering the return period used in the thesis (100 000 years), the water levels at the Swedish nuclear power plants are not expected to exceed DBFL.The other part of the thesis consists of a historical study of extreme weather-related events. The results of this study indicate that no historical events seem to have occured which would indicate a higher risk of flooding than the one suggested by the statistical study. .

How streaming media can be used in commercial mass
distribution

Mass distribution with techniques as multicast and peer-to-peer are becoming increasingly important in the Internet. Today the distribution of sound and video over Internet, so called streaming media, is static due to the unicast method. This results in a linear increase of distribution costs and therefore no conditions for commercial scalability. This thesis describes why multicast may be the only scalable alternative for commercial mass distribution of streaming media over Internet. Mass distribution through peer-to-peer technology promises a lot but is fronting a couple of great challenges, for example asymmetric bandwidth, locality and legalization.

Tillbaka till framtiden - om svensk filmdistribution i den digitala eran

Why is the e-revolution of the Swedish film distribution lingering? In attempting to answer that question, this qualitative study depicts the distribution market of Swedish film and its actors. Thirteen interviews with representatives of the industry have been conducted in search of an understanding of the current situation. Two important conclusions are made. One is that the strong interdependency between the actors of film distribution is inhibiting the acting space of those who seek change.

Mätning i nätstationer - nyttor och problem

The purpose of this study has been to investigate advantages and problems with distributionsystem metering in substations. This report is a study in cooperation with Göteborg Energi.The analyses in this report are made for GENAB, a subsidiary company of Göteborg Energi.To analyse advantages and problems in advance is interesting information for GENAB. Theresult of the report could be based upon whether installation of metering in distributionsubstations will be implemented and in that case which kind of measurement that is relevant.The most relevant and strategic place to implement measurement is at the distributionsubstations on the secondary side (400V), this is due to the placement of the currenttransformers. The measurements in this study involve current, voltage, power, power factor,temperature, energy and power quality.Measuring instruments that are relevant to implement are intended to measure current,voltage, power, power factor, energy and, possibly, power quality in the same measuring unit.It is desirable to have a measuring instrument that measures both energy and power qualitybut since it is most often a cost question, it can be established that energy meters have a lowercost.Metering in distribution substations gives a better illustration of the power network. Thisresults in many advantages for GENAB.

Framtidens elnät : Hur elbilar och solceller påverkar på det lokala elnätet

The purpose of the project is to determine the impact of solar cells and electrical vehicles on the future electricity grid and distribution network. Future electricity grids will be affected differently than it does today. Therefore, it is important to determine the impacts so that the current electricity distribution system can be developed and redesign to achieve the future demand. In Sweden, government has changed rules and laws in order to make it easier for private sector to invest in renewable energy sources. Our project focused on the impact of the solar cells and electric vehicles on the low voltage electricity distribution.

1 Nästa sida ->