Denna examensrapport redogör för hur man kan få en kortslutningsskyddadoch säker inkoppling av en DC-länk mellan två skiljda elektriska system.Rapporten bygger på hur en lastbil ska kunna få en större säkerhet för attbibehålla sina elektriska bromsar om tex ett av bromssystemen tappar sinordinarie matning.Lastbilens bromssystem består idag av två skiljda elektriska system med ett 24volts strömförsörjande batteri vardera. Det ingår två stycken elektriskabromsar i varje system. Om det tex blir fel på en av bromsarna och dennapåverkar ett av systemen vill man kunna koppla bort denna enskilda bromsmed sitt system. Man vill även kunna försörja den fungerande bromsen somsitter i samma system via en så kallad Axle Link. Denna strömmatningslänksitter mellan två hjulpar på samma axel.I denna studie undersöktes möjligheten att realisera en kortslutningsskyddadoch säker DC-överföring via en Axle Link, i första hand med diskretakomponenter.

In today?s society, safety in a workplace is an important factor to any organization. Focus on improving the working conditions by making them safer through technology is taking us into a time where we rely on technology to keep us safe. How well developed the technology may be, it is still not enough to keep us entirely from harm. Human error will always be a factor in the human interaction with a workplace.

A good power quality can be an important prerequisite to achieve a sustainable society. Scandinavia's electrical system is in many respects superior, and Sweden has a fossil free electricity generation at 97 % and a reliability of electricity distribution at 99.98 %. Meanwhile, the EU has an ambition to expand the electricity market in order to achieve a joint trading business across Europe. This cross-border market will result in a large proportion of fossil energy sources integrated into our electrical system, which also leads to an increased need for renewable electricity production in Sweden. One part of this development is to increase the share of renewable micro generation that is locally or regionally connected to the power grid.

A future expansion of wind power in the Nordic power system makes the balancing for the transmission system operator Svenska Kraftnät (SvK) more complicated. Up to the hour of delivery the balance responsible parties? (BRP) makes prognoses and plans, for consumption and production, to help maintain the balance in the electrical grid. How well this is accomplished is affected by the setup of the market design. Therefore SvK has proposed the following possible changes in market design: Increase the imbalance costsIntensify the regulation of imbalancesIncrease the temporal resolution on the different marketsPresent the prices for balancing power in real-timeModify the balancing market to simplify auction of consumption bidsA mapping over the BRPs? processes within planning and trading on the day-ahead, intra-day, and the balancing market has been performed in this thesis.

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.

Modern technology and fast development of heat pumps, the hunt for savings in energy consumption and the strive for environmentally friendly energy sources, convenience, and financial profit, have made heat pumps a reasonable alternative for the heating of houses.When the heat pump starts it will consume a considerable amount of current, which may result in a short-lived voltage-drop if the power grid is weak compared to the start-up current.The company Fortum Distribution which owns and administrates electrical network is interested in an investigation that deals with heat pumps affect on the quality of electricity.The purpose of this investigation is to study fast electrical fluctuations (flicker) as a result of start-up currents for single as well as multiple heat pumps on the same electrical station and from this evaluate whether there will be any problems installing heat pumps..

Simulation is a vital tool during development of JAS 39 Gripen, since money and time can be saved.The Auxiliary and Emergency Power System, AEPS, is a subsystem of the secondary power system in Gripen. It has the function of providing the aircraft with electrical and hydraulical power before activation and after deactivation of the main engine. The system also functions as backup in case of a safety critical problem in the main power supply system. The system basically consists of a control unit and an auxiliary gearbox. The gearbox is driven by an air turbine.

In this thesis is studied the electrical load of Paradisskolan with respect to power quality and energy consumption. The school's owner Trollhättans Tomt AB is also interested to know if they can reduce their costs by changing to smaller meter fuses. A recurring ground fault that?s been recorded from powerpanel A1A has been investigated. The school's equipped with an electrical bonding system, harmonic filters for the third harmonic currents, TN-S system from feeding transformer and groundfault monitoring.

As requested by the company Husqvarna AB, we have developed a prototype of an electrical start device to a chainsaw. This was done through the development of new details in Catia, which has been integrated with existing details. Electrical components have been purchased by HAB electronics. In parallel with the modeling calculations was done, which was the basis for determine dimensions and the choice of an electric motor and gears. Prototype 1 improved gradually and led to prototype number 2, which became the final result.

Sweden has long had access to low electricity prices due to the wide availability of hydro and nuclear power. This has now changed because of today's rising electricity rates resulting in increasing heating costs for properties, especially in the properties with electric heating systems."Ankaret" is a parish for "Svenska Alliansmissionen", which is located at "Gullbrannagården".The parish has installed electrical radiators and an exhaust ventilation system that makes the energy demand high due to the large ventilation flows. The building was built as the price of electricity was still low and would reduce energy use today by combining its heating system with an air/air heat pump. The heat pump delivers more heat into the room than the electrical energy that it uses. This lowers the electricity needs.

Vattenfall and Svenska Kraftnät perform start-up tests, where hydropower generators are used to power up the electrical grid in case of a blackout. To monitor the electrical grid, Phasor Measurement Units (PMU) are used. Each PMU is individually equipped with a GPS-receiver to precisely timestamp the data relative to the official time UTC. During the test, it is also of interest to timestamp the measurement signals from individual hydropower generators to later compare with PMU-data, and thus study the power grids impact on the generator. The aim is to work out an appropriate method to make these measurements and to build a data acquisition system, capable of timestamp data relative to UTC, from a generator in one of Vattenfalls hydroelectric power stations. The problem is that the generator is located in an underground station which hampers the reception of GPS-signals and wiring should be avoided if possible. Time synchronization has been solved by using Vattenfalls network, which is synchronized by the network protocol NTP.

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.

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.

This is a thesis for a Bachelor Degree Project, performed in the subject MechanicalEngineering. The students Roger Malmberg and Simon Hagberg have carried out adesign project on behalf of the recently established company J&D Assisting systems,located in Halmstad.The project consisted in developing J&D's first prototype of a power assisting solutionfor wheelchairs. A power assisted wheelchair combines human power, which is deliveredby the arms through the pushrims, with electrical motors, which are powered by a battery.The power assisted wheelchair is aimed at customers, who have used a regularwheelchair for a long time, but who have become weaker or just need additional powerwhen driving uphill. This kind of wheelchair will provide additional power for users,which will spare their wrists, elbow and shoulders. The product is torque sensor free andinstead it relies on the velocity.

The electrical grid needs to be changed in the future in order to manage more distributed and renewable generation and also to make it possible for electricity consumers to be more active and aware of their electricity consumption. This future grid is usually referred to as a smart grid. With the transition to a smart grid, new challenges occur. One method to determine those challenges is to perform risk and vulnerability analyses. InStockholm, the new urban district Stockholm Royal Seaport is built.