Detta examensarbete beskriver en nätanalys av delar av Ale Els nät för att underlätta vid framtida reinvesteringar i nätet. Examensarbetet syftar till att göra en sammanställning av reinvesteringsbehovet för två 10 kV linjers tillhörande lågspänningsnät och deras transformatorstationer. En nätanalys kan utföras på olika sätt och innehålla flera olika delar. Denna nätanalys omfattar en beskrivning av det aktuella området och nätberäkningar som utförts i dpPower för att undersöka vilka delar av nätet som inte är optimalt utformade. Detta har tillsammans med fältbesök och undersökning av störningsstatistik mynnat ut i olika åtgärdsförslag. Nätstationerna av typen "Combi Lomma" har rangordnats efter deras behov att ersättas. Därefter har åtgärder vid 9 olika nätstationer föreslagits med målet att minska spännings-fall, bryttider, belastningsgrader och öka driftsäkerheten. Åtgärdsförslagen innefattar som ett exempel en kund med 17 % spänningsfall, 8,9 s bryttid där delar av ledningen har en belastningsgrad på 130 %. Efter att luftledningen har ersatts med nedgrävd kabel och ett kabelskåp installerats har det beräknade spänningsfallet minskats till 3,9 %, bryttiden till 0,047 s och belastningsgraden till 49 %. / This thesis describes a grid analysis of parts of Ale El’s grid to facilitate future re-investments in the grid. The thesis aims to make a compilation of reinvestment requirements for two 10 kV line associated low voltage grid and their substations. A grid analysis can be performed in various ways and include several different parts. The grid analysis includes a description of the area and grid calculations performed in dpPower to investigate which parts of the grid that are not optimally designed. This, together with field visits and study of power outage statistics resulted in various proposals for action. Substations of type "Combi Lomma" have been ranked according to their need to be re-placed. Thereafter measures have been proposed in 9 different substations with the aim to reduce voltage drop, break-times, overloads and increase reliability. As an example of these measures is improving the quality of electricity for a customer with 17% voltage drop, 8.9 s break-time and parts of the line supplying the costumer has a load rate of 130 %. The overhead line that is supplying the costumer at present could be replaced with cables in the ground and a distribution board could be installed. This would result in a calculated voltage drop reduced to 3.9%, break-time to 0,047s and the load rate to 49%.

Recent trend of intense urbanization in combination with a low construction rate have resulted in a serious shortage of available housing in Swedish cities particularly Stockholm. To tackle an existing housing shortage an increased construction rate appears to be a necessity. However a challenge still remains to find available land to build on, especially in central parts of Stockholm. Through decking of central roads and/or railways attractive land is created on the surface of the deck construction. Acting as a positive proposition in this regard, decking should however be done with caution as it also brings about challenges and less appealing consequences. Among others, these include continuous costs from maintenance and/or reinvestment over its lifetime, a complicated relationship between stakeholders, and costly socioeconomic impact during disruption of traffic flow. Consequently, there exists a need for maintenance that is well suited to these challenging conditions. The master thesis constitutes an analysis of how maintenance is conducted for decking constructions in Stockholm. A case study of Södra Station and Söderledstunneln was completed. The case study utilized a qualitative approach in collection of data through review of relevant literature and archives, as well as semi-structured interviews with the primary stakeholders Stockholms stad, Trafikverket, and housing cooperatives. The objective with the analysis is to contribute with research on how maintenance should be applied to facilitate sustainable development of decking constructions located in central Stockholm. The result and conclusion of the analysis is that responsibility of maintenance should lie with a stakeholder that has proper competence and resources as well as a long term and local oriented perspective. Furthermore, a dialogue should be established amongst the stakeholders with maintenance responsibilities. Lastly, a maintenance strategy that focuses on preventive maintenance based on optimization from data collection with a degree of automated inspection on a collective platform should be applied. With these measures in place cost efficiency over the constructions lifetime will be achieved without jeopardizing the reliability of traffic flow thus contributing to sustainable development.