Abstract In high voltage Substations there is an increasing demand for computerized equipment, and automation of operation and supervision. The future primary equipment will provide the possibility to collect more information and to provide better control for improved effectiveness. Since ABB has got a large customer target, each product must be custom made to fulfil the customers (often from different countries) demands. Later these products will be configured by engineers who may not be familiar with the tools used at ABB. This is a very expensive and time consuming.

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.

In Stockholm, Johanneshov the Slaughterhouse area (Slakthusområdet) can be found. A number of companies have gathered there providing the Stockholmers with meat products. This area has a great need for cooling to supply large cold storages. To facilitate this, a central cooling system has been built, supplying the area with effective and safe cooling.The aim of this master thesis study is to give hints to energy efficient and reliable changes that can be put in place at a low marginal cost depending on the future activities in the area. The suggested changes will be presented to the company Bravida (managing the system), which also desires a deeper understanding of the energy flows through the central cooling system.Firstly visiting the site with proper guidance, we have then tried to understand the function of the system including which machines and media that are used.

Sweden will, in accordance with the EU-directive 2003/54/EC, move from post-regulating the electricity power grid-tariffs by using a fictitious grid, to a regulation in advance which uses the actual power grid as a starting point. For this purpose a component breakdown of the grid needs to be made to determine the value of the network and by that the tariff price that is reasonable for the network business in question to charge.The primary breakdown criteria is the voltage-level and type of region. Voltage-level is crucial for the cost and complexity of a grid-part, because the higher the voltagelevel is, there are more and stricter laws and rules to follow. This work is limited to the distributionpart of the grid, in other words voltage levels from 20 kV and below.The type of region is crucial to the type of components you can and want to use. In city environments both overhead-wires and independent Substations are undesirable for both practical, safety and aesthetic reasons.

Outages in the electric grid can be costly for society. Because of this, reliability is one of the parameters used to regulate network companies. Reliability in electrical grids can be measured with SAIDI, system average interruption duration index, which for Fortum Distribution has increased in Stockholm?s distribution network (11 kV) in the early 2000?s.By using outage data for Stockholm from 2011-2013, sets of parameters to be used for reliability calculations in the network information program Tekla NIS were derived. Two different options for investment were then analysed: changing old cables with high fault frequencies, and installing automatic switching in distribution Substations.

Detta examensarbete är utfört på uppdrag av Rejlers Ingenjörer i Göteborg. Syftet med arbetet är att genom en projektering övergripande presentera utförandet, komponenter, funktioner, ekonomi och situationsplaner för två förslag på stationsutformningar i samband med en ombyggnation och utvidgning av en transformatorstation. Transformatorstationen har i nuläget två spänningsnivåer på 40 kV och 10 kV. I samband med ombyggnationen skall stationen kompletteras med ytterligare en spänningsnivå på 20 kV, för anslutning av ett antal vindkraftverk. För att anläggningen skall uppfylla grundläggande krav, utförs projekteringen genom att sortera och sammanställa relevant information från gällande föreskrifter, standarder och tekniska riktlinjer.

A problem in the field of district heating is the oil burners needed to provide power when a peak load occurs. One possible way of reducing the needed amount of oil is to reduce the power demand for space heating in the district-heating Substations when the need for district heating water exceeds a certain limit. This can be done by use of a locally working controller function.In this Thesis the options concerning load priority are evaluated. To evaluate the potential for using controller functions concerning peak load priority an experiment was brought out in a chosen district-heating Substation. The impact on the indoor thermal comfort during a heat reduction was also taken into account.

During the period 2009-2013, investments in the Swedish national grid increase by a factor of ten compared to previous years. In order to fulfil their mission to manage the national grid in a safe, efficient and environmentally sound way, Svenska Kraftnät (Swedish National Grid) needs to take all these perspectives into account while planning new investments. To compare and relate perspectives of technology, economy and environment the same yard stick must be used. That yard stick is commonly money. A problem arises however as environmental issues are difficult to price.The purpose of this master?s degree project was to develop a tool for evaluation of environmental impact related to investments in the Swedish national grid.

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.