Background. Smart grid is a new technology that focuses on utilising renewable energyalongside the current infrastructure. It aims to contribute to a sustainable future by implementingIoT devices in the electrical grid to adjust electricity flow and increase energyefficiency. By combining the current infrastructure with information technology manysecurity questions arise. This paper focuses on the authentication of the IoT devicesconnected with the MQTT protocol.Objectives. The study aims to discover a preferable MQTT authentication methodadapted for Techinova’s infrastructure with their requirements in consideration.Methods. A literature review was performed to obtain fundamental authenticationmethods and to distinguish different security approaches. Experiments were executed ina test environment to gather detailed information to gain a deeper understanding anddiscover security vulnerabilities.Results. The results derive from three experiments comparing the selected authenticationoptions security flaws.Conclusions. The results suggests that implementing TLS contributes to a secure authenticationand communication between the IoT devices and the broker without delayingthe transmission. However, further research could obtain other relevant data eventuatingin different results.

The aim of this project was to devise an algorithm for three phase AC power grid measurements that could be utilized in an excitation system for controlling generators. This application requires fast and accurate measurements even when the voltages in the power grid are characterized by unbalanced three-phase, frequency variations and harmonic distortions. Phase locked loop algorithms are used in grid synchronization techniques and are developed to withstand disturbances in the power grid. A DSOGI-PLL was implemented on a PLC and then evaluated. The DSOGI-PLL was tested with input voltages generated by a relay testing system. The result showed that the DSOGI-PLL could measure positive sequence component RMS and grid frequency of unbalanced three-phase voltages and voltages characterized by frequency variations and harmonic distortions. However, the measurements response time and accuracy did not meet the requirements for application in excitation systems.

The transport sector always strive towards reduced fuel consumption for heavydutyvehicles. One promising control strategy is to use Pulse and Glide. Themethod works by acceleration to a high speed and then glide in neutral gear to alow speed.Two different control strategies and four different glide options were investigated.The two strategies were either to follow the optimal BSFC-line or using optimalcontrol. For each strategy, different velocity spans between the upper and lowervelocity were tested.The results show that the fuel consumption can be reduced up to 8.1 % comparedto a constant speed driving strategy. The fuel consumption was reduced the mostfor lower velocities and if the difference between the upper and lower velocity forthe Pulse and Glide strategy was kept small. The fuel saving can be explaineddue to increased engine efficiency during the pulse. The results also show thatthe difference between the rule-based and optimization based control strategy issmall. It can be concluded that a near-optimal strategy for a heavy-duty vehicleutilizing Pulse and Glide is to always pulse on the optimal BSFC-line.

Som en del av Elsäkerhetsverkets klimatanpassningsarbete undersöktes i detta examensarbete vilken kunskap som finns kring personsäkerhet vid översvämning av lågspänningsanläggningar, samt huruvida vanligt förekommande elapparater och elcentraler läcker ut ström när de nedsänks i vatten. Informationsinhämtning skedde genom sökning i artikeldatabaser. Sökningarna resulterade främst i artiklar om person-säkerhet i andra typer av vattenmiljöer med elanläggningar, i huvudsak båt- och hamnmiljöer. Mätningar på ett urval av eluttag, kopplingsdosor och elcentraler nedsänkta i vatten respresenativt för dagvatten visade att samtliga läckte ut ström till en jordelektrod på 1,2 m avstånd, förutom en elcentral av metall med jordat hölje och stängd dörr. De flesta läckströmmar var större än gränsvärden för farlig strömstyrka. Säkringar på 16 A och 25 A löste ut först vid vattenkonduktivitet representativt för havsvatten. Vid mätningarna uppmättes farliga potentialer i vattnet kring apparaterna och centralerna. Simuleringar med dataprogram visade att det elektriska fältets utbredning kunde påverkas stort av den specifika geometrin i rummet, med främmande ledande delar och olika konduktivitet i väggar och golv. Det bekräftar att strömfördelning och det elektriska fältets utbredning i reella översvämningsmiljöer  är svårförutsägbart. / As a part of the work by the Swedish Electrical Safety Authority to adapt rules and regulations to future climate changes, this thesis investigate the present knowledge about personal safety during flooding of low voltage distribution systems and private electrical utilities. It also investigate if common electrical equipment and distribution boxes leak current when immersed in water. Information seeking was done by searches in article databases. The search results mainly concerned personal safety in other types of  environments with water and electric facilities, mostly boats and marinas. Measurements on a selection of electric equipment and distrbution boxes immersed in water, representative of surface water, showed that all but one produced leak current in the water to a ground electrode at a distance of 1,2 m. Only a metal distribution box with grounded casing and closed door did not produce leak current in the water. Most of the leak currents exceeded limits for dangerous current levels. Dangerous potenatials where recorded in the water surrounding the equipment. Simulations with computer programs showed that the distribution of the electrical field could be greatly affected by the particular environment, consisting of different metal structures common in buildings and different conductivity in walls and floor. It confirms that current split and distribution of electric fields i real flooded environments are hard to predict.

För att skapa konkurrenskraft krävs alltid optimering, av flera olika processer, mot mer energi- och kostnads-effektivitet. Anläggningen som används i detta projekt, ett kraftvärmeverk som byggdes så sent som 2015, har dragits med vad som verkat vara en icke optimal drift av tryckluftssystemet med tre identiska, frekvensomformarstyrda kompressorer. Målsättningen med detta projekt var att ta fram förslag på en mer optimal styrning av anläggningens tre kompressorer samt att implementera den för att genomföra en analys om resultatet. En nulägesanalys visade att det fanns utrymme för förbättring av styrningen samt att en del regulatorparametrar skulle behöva optimeras. Två regleringsförslag togs fram, som till stor del vara ganska lika men med den stora skillnaden att förslag ett använda sig av kompressorernas tryckregulatorer och det andra förslaget styrde kompressorernas varvtal direkt från PLC:n. I slutet på detta projektet, när de nya regleringsförslagen skulle implementeras, var anläggningen i ett tre veckor långt driftstopp för underhåll. Detta påverkade optimeringen genom att förbrukningen av tryckluft var låg. Detta skulle lett till att en parameteroptimering inte skulle blivit helt optimal. Eftersom kompressortillverkaren inte valde att samarbeta fanns dessutom ingen möjlighet att utföra en parameteroptimering på alla regulatorer. Trots dessa omständigheter så har en viss optimering troligen skett med det nya regleringsförslaget. / In order to create competitiveness, optimization towards more energy and cost efficiency is always required, of several different processes. The plant used in this project, a cogeneration plant that was built as late as 2015, has been drawn with what appeared to be a non-optimal operation of the compressed air system with three identical air compressors whom are controlled by frequency converters. The objective of this project was to produce proposals for a more optimal control of the plant's three air compressors and to implement it to carry out an analysis of the result. An analysis of the origin operation showed that there was room for improvement of the control and that some controller parameters would need to be optimized. Two regulatory proposals were developed, which to a large extent are quite similar but with the great difference that the first proposal make use of the compressors' pressure controllers and the other proposal controlled the speed of the compressors directly from the PLC. At the end of this project, when the new regulatory proposals were to be implemented, the facility was in a three-week downtime for maintenance. This affected the optimization because the consumption of compressed air was low. This would mean that a parameter optimization would not be completely optimal. Moreover, since the compressor manufacturer did not choose to cooperate, there was no possibility of performing a parameter optimization on all controllers. Despite these circumstances, some optimization has probably occurred with the new regulatory proposal.

This report is about how to design and fabricated a wireless energy transfer system which is printed on flexible photo paper. That is a technology used to print conducting tracks on paper, or even entire circuit system. The circuit of wireless energy transmission is half bridge converter with spiral coil as the inductance which are etching in primary side and printing in secondary side.The procedure of fabrication will be introduced. While realizing the feasible simulation circuit, the optimal transmission energy system components are mounted according to the requirements. While looking for the best efficiency, it’s also neccessary to consider the appropriate size of the system. In the end of this report there will be some analysis which is aimed to identify where the largest electrical losses are located. Compared with ordinary PCB circuit board, printed circuit on paper makes the whole system very flexible and portable. When the primary side as close with secondary side, The efficiency is almost 72% while the 60Ω as the load. The output power is 10.68w. On the other hand, the ink of printed circuit on paper has high resistivity, which affects the efficiency of radio power system. However, for different paper substrates, the efficiency of wireless charging system will not be affected.

Dala Energi has large-scale plans for grid development and wants to have a better understanding of their current reactive power levels along with a future prognosis based on their plans. Changes in line inductance, shunt capacitance, area and placement put Dala Energi on the path to higher charging currents and higher reactive power generation. In addition to causing concerns in their own grid, the increased reactive power generation can present challenges for the owner of the overlying grid. Transmission of reactive power upwards is not permitted in the current contract. Dala Energi’s grid is divided into 3 separate regions with a total of 19 larger substations, 12 of which are points of connection with the overlying grid. At times, 8 of the substations have transmitted reactive power upward and soon it will be all 12. Region 1, where the 20-kV grid is located, is the biggest problem-area today, with upward-transmissions of 1 to 3 MVAr quite common and a considerable increase expected. Region 3 contains more than double the underground cable as the other two areas and might have had much greater side effects from the high shunt capacitance were it not for 3 industrial customers who consume a large portion of reactive power. In the coming years, however, Region 3 is expected to have capacitive reactive power levels nearly equal to those of Region 1. The combined reactive power baseline for all regions is expected to drop by 8.24 MVAr in the coming years. The owner of the overlying grid controls Dala Energi’s 5 largest capacitor banks which have a rated capacity of 11.6 MVAr. With the entire capacity almost always connected, the upward transmission of reactive power becomes much greater. It would be very advisable to meet with the owner, discuss interaction between the two grids and examine the details of the current contract. Compensation for excessive generation of reactive power is needed and is going to be essential in the future. The short-term variation of reactive power levels is so great that the use of fixed rating shunt reactors is ill-advised, especially under the current contract. Compensation with variable shunt reactors is recommended.

Volume visualization has been made available on the web using the Direct Volume Rendering (DVR) technique, powered by the WebGL 1 API. While the technique produces visually pleasing output, the performance of the prototypes that implement this leave much desired. 2017 saw the release of the next version of WebGL, WebGL 2.0 and the introduction of WebAsssembly. These APIs and formats are promising tools for formulating a DVR application that can do high performance rendering at interactive frame rates. This thesis investigates, implements and evaluates a prototype application that utilizes the optimization methods of Adaptive Texture Maps, Octree Empty Space Skipping and Distance Transform Empty Space Skipping. The Distance Transform is further evaluated by a CPU bound and a GPU bound algorithm implementation. The techniques are assessed on readily available off the shelf devices and hardware. The performance of the prototype application ran on these devices is quantified by measuring computation times of costly operations, and measuring frames per second. It is concluded that for different hardware, the methods have different properties. While higher FPS is achieved for all devices by utilizing some combination of the optimization methods, the distance transform is the most consistent. A discussion on embedded devices and their quirks is also held, where memory constraints and the resolution of the data is of greater importance than on the non-embedded devices. This results in some suggested actions that can be taken to also potentially enable high-performance rendering of higher resolution data on these devices.

Thesis explores the question of whether one-diode model can be extracted using soft-computing approaches based on indoor conditions. In thesis, three algorithms were selected using MATLAB for implementation, analysis and comparison. Thesis has proved that under indoor conditions, all three algorithms can accurately extract photovoltaic parameters under most illumination levels, but the extracted photovoltaic parameters cannot satisfy the physical meaning of photovoltaic parameters.

A general local powerline has implemented to mimic a lifelike powerline build around 1960s in thecountryside. Since reconstruction is needed a new projection is made of the area to improve the powerquality. The projection includes the old transmission lines will be replaced with underground powercables to make it weatherproof. The implication of underground power cables leads to smaller distancebetween the phases which generates greater capacitance. Due the increase will make the capacitivecurrents greater as well which affect the power quality for the costumers in the area. The projectionmust be adapted to the increase of earth fault currents which the capacitive currents contribute. The regeneration of the old and new power lines consists a sketch of terrain, merge of the powerconsumption, electrical fuses, line diagram, sizing transformers and right dimensions of cables. Calculations on capacitive fault current, voltage drop as well as neutral grounding reactor (a resistanceparallel with an inductor) was executed. Calculations of the powerline followed Swedish standard andthe neutral ground reactor after the norms of Swedish electrical industry. Regard to the projection, including underground cables, the capacitive fault currents increased with 46,75 times compared to transmission powerlines at 10 kV. Calculations of the neutral ground reactorresulted in 5,25 Henry for the inductor and 1154 Ohm for the resistor to compensate the gain. The conclusion is that weatherproofing the powerline at 10 kV leads to compensating otherwise the powerquality and selectivity will be affected. That result in a more expensive arrangement cost forunderground cables compared to transmission.