As part of the international EU project Integrid, Ellevio has started a pilot project where measurement equipment has been installed in secondary substations in Stockholm Royal Seaport. The purpose of the pilot project is to improve operation, maintenance and future planning of the grid. This thesis focuses on predictive maintenance and data analysis of power quality parameters and aims to cover several areas within these two categories to answer the following research questions: -In what ways can the life-cycle and faults of components be used as a basis for predictive maintenance? -Are there any measurable parameters - currently being monitored or not - that can be useful for Ellevio in terms of maintenance and grid development? -Is the installation of more monitoring systems worthwhile, and if so, what should be monitored? -Is it possible to find indicators that allow for predictive maintenance to reduce the interruption time and maintenance cost? The main results are that the focus should lie on middle voltage (MV) cables due to its significant contribution to SAIDI and SAIFI. Monitoring partial discharges in MV cables could potentially lower the frequency of faults. A study needs to be conducted to establish the extent of partial discharges as a source of faults. Furthermore harmonic content was found to have a large impact on transformer losses and this parameter should be considered when dimensioning new secondary substations. Another parameter that had interesting results is the current unbalance which led to high neutral currents and caused high losses.

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ABB HVDC is a manufacturer of optical current transducers (OCTs) are used which are used to measure alternating currents in high voltage applications. The sensor used today is based on a current transformer and measures alternating currents between 100 and 4000 A. With the current transformer there are disadvantages due to its core of magnetic material which saturates at high currents. As the core goes into saturation, the number of different variants of current transducers increases re-garding rated currents, measurement requirements and behavior in short-circuit currents and transients. Due to such a limitation, there is the need for an alternative solution. The Rogowski coil is just like the current transformer based on Faraday's law of in-duction. Instead of several different variants, a solution with Rogowski coils can be varied with different measuring ranges of the sensor electronics. Therefore, the possibility of implementing a Rogowski coil in an OCT is being investigated. An OCT consists partly of the sensor itself but also an electronics unit and an optical in-terface unit (OIU). Since the signal from a Rogowski coil is proportional to the derivative of the current in the measurement object, a type of integrator is needed to recreate the signal. The possibility of having either an analog or digital integrator exists, but a digital can bring benefits such as reduced delivery time. By utilizing existing circuits on the OIU, a digital integrator could be implemented. In the work, an integrator function has been created in Matlab to recreate the signal. A scale factor was determined to minimize the amplitude difference between reference sensors and the Rogowski sig-nal. The work shows that current measurement with the Rogowski coil where the fre-quency is varied results in an amplitude difference between the reference sensor and the Rogowski coil. The amplitude difference has a linear trend and could be offset by a frequency coefficient. The work also discusses proposals for further tests that should be performed to identify how different factors affect a current measurement. / På ABB HVDC tillverkas optiska strömgivare (OCT) som används för att mäta väx-elströmmar i högspänningsapplikationer. Givaren som används idag är baserat på en strömtransformator och mäter växelströmmar mellan 100 och 4000 A. Med ström-transformatorn följer nackdelar på grund av dess kärna av magnetiskt material som går i mättnad vid höga strömmar. Till följd av att kärnan går i mättnad så ökas anta-let olika varianter på strömgivare med hänsyn till märkströmmar, mätkrav och bete-ende vid kortslutningsströmmar samt transienter. På grund av en sådan begränsning finns behovet av en alternativ lösning. Rogowski-spolen är precis som strömtransformatorn baserad på Faraday’s indukt-ionslag. En lösning med Rogowski-spolar kan istället för flera olika varianter, varie-ras med olika mätområden hos givarelektroniken. Därför undersöks möjligheten att kunna implementera en Rogowski-spole i en OCT. En OCT består delvis av själva givaren men även en elektronikenhet samt en optisk gränssnittsenhet (OIU). Eftersom signalen från en Rogowski-spole är proportionell mot derivatan av ström-men i mätobjektet så behövs en typ av integrator för att återskapa signalen. Möjlig-heten att ha antingen en analog eller digital integrator finns, men en digital kan med-föra fördelar som exempelvis minskad leveranstid. Genom att ta nytta av befintliga kretsar på optiska gränssnittsenheten skulle en digital integrator kunna implemente-ras. I arbetet har en integratorfunktion skapats i Matlab för att återskapa signalen. En skalfaktor bestämdes för att minimera amplitudskillnaden mellan referensgivare och Rogowski-signalen. Arbetet visar att strömmätning med Rogowski-spole där frekvensen varieras medför en amplitudskillnad mellan referensgivare och Rogowski-spole. Amplitudskillnaden har en linjär trend och skulle kunna motverkas genom en frekvenskoefficient. I arbe-tet diskuteras även förslag på ytterligare tester som borde utföras för att identifiera hur olika faktorer påverkar en strömmätning.

Turbocharging is a way to stay competitive on the market where there are increasing demands on fuel consumption and engine performance. Turbocharging lets the engine work closer to its maximum power and thereby reduces the relative losses due to pumping and friction. The turbocharger is exposed to big temperaturedifferences and heat flows will occur both internally between the turbine and the compressor as well as between the turbocharger and its surroundings. Away to get a better understanding of the behaviour of the turbocharger is to understand the heat flows better. This thesis is therefore aimed at investigating theeffect of heat transfer on the turbocharger. In the thesis, different ways of accountfor the heat transfer within the turbocharger is investigated and a heat transfermodel is presented and validated. The model can be used as a tool to estimate theimportance of different heat flows within the turbocharger. A set of heat transfer coefficients are estimated and the heat transfer is modelled with good accuracyfor high engine loads and speeds.

In recent times there has been a substantial increase in research interest of soccer due to an increase of availability of soccer statistics data. With the help of data provider firms, access to historical soccer data becomes more simple and as a result data scientists started researching in the field. In this thesis, we develop prediction models that could be applied by data scientists and other soccer stakeholders. As a case study, we run several machine learning algorithms on historical data from five major European leagues and make a comparison. The study is built upon the idea of investigating different approaches that could be used to simplify the models while maintaining the correctness and the robustness of the models. Such approaches include feature selection and conversion of regression prediction problems to binary classification problems. Furthermore, a literature review study did not reveal research attempts about the use of a generalization of binary classification predictions that applies different target class upper boundaries other than 50% frequency binning. Thus, this thesis investigated the effects of such generalization against simplicity and performance of such models. We aimed to extend the traditional discretization of classes with equal frequency binning function which is standard for converting regression problems into the binary classification in many applications. Furthermore, we ought to establish important players’ features in individual leagues that could help team managers to have cost-efficient transferring strategies. The approach of selecting those features was achieved successfully by the application of wrapper and filter algorithms. Both methods turned out to be useful algorithms as the time taken to build the models was minimal, and the models were able to make good predictions. Furthermore, we noticed different features matter for different leagues. Therefore, in accessing the performance of players, such consideration should be kept in mind. Different machine learning algorithms were found to behave differently under different conditions. How-ever, Naïve Bayes was determined to be the best-fit in most cases. Moreover, the results suggest that it is possible to generalize binary classification problems and maintain the performance to a reasonable extent. But, it should be observed that the early stages of generalization of binary classification models involve a tedious work of training datasets, and that fact should be a tradeoff when thinking to use this approach.

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This report covers a project that set out to create our own and implement another existing measurement system that measures the power consumption in different student residences with higher resolution then what is currently offered by Vattenfall. This is important since there is a problem in Uppsala with a lack of power from the electrical grid which limits Uppsalas ability to grow as a city. Different dorm rooms in the housing area Gamla Studenstaden were then measured and data with the resolution of 1 minute was then analysed. This data was then used in order to answer which type of accommodation is most efficient with its power usage in relation to the amount of rooms. This report also wanted to answer how different types of accommodations cause spikes in their power usage which are only possible to spot with the higher resolution. The resulting data show that one-room apartments has relatively low power consumption over the day but contribute to so called power spikes which cause large load on the power grid. The dorm rooms did however seem to have a more distributed power consumption over the day.

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In 2014 KTH Royal Institute of Technology initiated a space technology and research center, KTH Space Centre. MIST (MIniature Student saTellite) is the rst student project conducted at KTH Space Centre and also the rst student satellite from KTH with a predicted launch in 2017. This report includes the thermal analysis and control of the spacecraft MIST. One of the main systems in a spacecraft is the thermal control system. In order for the payloads and subsystems to withstand the harsh thermal environment in space a thorough thermal analysis is needed. In this project the thermal model has been built and thermal control design of the spacecraft has been started. As a start a preliminary thermal analysis was performed where the spacecraft was approximated as a sphere in order to get some estimates on the temperature in orbit due to the space environment. Furthermore the temperature decrease in eclipse was studied. Since most of the spacecraft will consist of Printed Circuit Boards (PCB) the thermal behavior of PCB has been investigated and as a part of this investigation a thermal vaccum chamber test was performed where the conductance from a PCB through the mounting interface to a metal plate was measured. This report will also guide the reader through the model built and assumptions made. As a part of the thermal control, Multi Layer Insulation (MLI) has been studied and modeled in two di erent ways which have been compared with each other in order to know the level of detail needed for the MLI model. Last but not least the design of the thermal control system has been started where some payloads have been wrapped in MLI and thermal contact conductance coecient has been changed in order to meet the thermal requirements of the payloads and subsystems.

The task of this master's thesis was to design a transformer test bench while focusing on safety and usability. There are several safety risks when working with high voltages, therefore the high demand for safety precautions. A bench was worked upon, and attachments, such as module frames and banana connectors were integrated into the bench. Further, a list of components were modied and installed on the new bench. A new design, using a magnetic non-contact safety interlock switch and an easy-to-apply circuitry, was proposed and implemented. In addition to the implementation, a code in LabVIEW was written in order to handle the measured data from the tests that can be performed on a transformer. Several tests were performed on a single-phase transformer and a three-phase transformer in order to verify the function of the transformer test bench, with respect to the design. Complications emerged due to random additive noise. After some work, the noise was suppressed and the results showed that the equipment worked well with the new design. Finally, a user's manual was written in order to guide the user through the wire connections, tests and the developed software in LabVIEW. / En transformatortestbänk avsedd för laborationer inom forskning och utbildning har utvecklats, där fokus har lagts på säkerhet och användbarhet, eftersom arbete med höga spänningar medför säkerhetsrisker. En bänk modierades för att möjliggöra fastsättning av moduler samt banankontakter. Vidare anskaades elektroniska komponenter, bearbetades och installerades. En design med en magnetisk switch samt lättanvända kretsar föreslogs. Dessutom skrevs en kod i LabVIEW med ett brett användningsområde. Ett 　flertal tester utfördes på en enfastransformator och en trefastransformator med syfte att säkerställa att komponenter- na fungerar väl ihop med den framtagna transformatortestbänken. En del komplikationer uppstod på grund av slumpmässigt, additivt brus. Detta gick dock att undertrycka. Det slutliga resultatet visade att kom- ponenterna fungerade väl ihop med den framtagna transformatortestbänken. Slutligen skrevs en användarmanual med syfte att instruera använda- re av transformatortestbänken beträande kopplingarna, testerna samt mjukvaran som är skriven i LabVIEW.