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  • 101.
    Benages Montolío, Sergio
    University West, Department of Engineering Science, Division of Automation Systems.
    Robot Behaviour Monitoring in Friction Stir Welding2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Friction Stir Welding is a solid state join process in which the heat need is produced by the friction of a tool on the work pieces. The tool rotates on the surface and also applies a force against it to create the needed friction. This technology does not use any consumable and does not produce any gas, which makes it cost effective, save for the operators and clean.

    The equipment used for this technology has been changing within the years. Milling machines were adapted to it at the beginning. After, specific machines for friction stir welding were developed, providing higher down force and control systems. Nevertheless, the lack of flexibility of machines made industrial robots became an alternative. Robots have limitations in terms of stiffness. But, they can be used to weld complex geometries and they can be used in large scale applications due to their flexibility and low cost.

    This project studies the process from the robot behaviour perspective. The main objective is to achieve a better understanding of the process to contribute to the continuous development of robotic FSW. An acquisition system was developed to monitor different signals from the robot such as, forces, torque, path deviation, and vibrations. The data acquisition system developed and mounted at PTC was tested and its limitations were examined. The developed system has been used for conducting different experiments: The differences between the robot system and a system based on a FSW machine situated at TWI were studied; and, in addition, the behaviour of the robot under different welding parameters was investigated.

  • 102.
    Benal, Yalcin Can
    University West, Department of Engineering Science.
    Discrete Event Simulation of Sawmill Process2023Independent thesis Advanced level (degree of Master (One Year)), 20 HE creditsStudent thesis
    Abstract [en]

    The Sawmill industry plays a crucial role in the forestry sector, providing the raw material needed for various industries such as construction, furniture, and paper production. Efficient production in sawmills is essential to meet the increasing demand for lumber and to remain competitive in the market. In this context, Discrete Event Simulation (DES) is a powerful tool for improving production efficiency by identifying bottlenecks, reducing lead times, and optimizing inventory levels.

    This thesis project aims to develop a simulation model using Discrete Event Simulation (DES) to improve the production flow in a Sawmill. The simulation model allows the company to test different scenarios, such as changes in production schedules, machine configurations, and inventory management, without disrupting the actual production. By answering two investigative questions, the report provides insights into the level of information needed for the simulation and the limits of the simulation model's capability to detect flaws in the production process.

    Accurate data is essential for building a reliable simulation model. Therefore, the report emphasizes the importance of collecting data on various aspects of the Sawmill, such as machine utilization rates, machine capacities, processing times, and inventory levels. The report also highlights the need for simplifications and assumptions to create an optimal model, as collecting data on every detail may not always be feasible. 

    The ExtendSim software is used to build the Discrete Event Simulation (DES) in this report. This software allows the modeler to create an accurate representation of the Sawmill's production flow and analyze the impact of different scenarios on the production process. The simulation model can help the company make informed decisions by identifying bottlenecks, reducing lead times, and optimizing inventory levels.

    In conclusion, this thesis project provides valuable insights into the use of Discrete Event Simulation (DES) to improve the efficiency of the Sawmill process. The simulation model developed in this report can help the company test different scenarios, reduce lead times, optimize inventory levels, and make informed decisions. The report highlights the importance of accurate data, simplifications, and assumptions in building a reliable simulation model. By leveraging Discrete Event Simulation (DES) as a tool for optimization, the Sawmill industry can enhance its productivity and remain competitive in the market.

  • 103.
    Bengtsson, Robert
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Claesson, Rickard
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Att designa ett kostnadseffektivt nätverk för det lilla företaget2018Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This paper goes through the process of designing a corporate network from scratch. The work clarifies some concepts in network design, how a simple requirement specification can look and how it is used in the process of creating a network that meets the customer's needs.

  • 104.
    Bennehag, David
    et al.
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Wulcan, Alexander
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Claesson, ommy
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Förstudie till ett stadstäckande och öppet WiFi i Trollhättan2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Förstudien behandlar den tekniska delen av ett teoretiskt stadstäckande öppet WiFi i Trollhättan, Sverige. Trollhättans kommun beställde en förstudie från Högskolan Väst som skulle agera beslutsunderlag till hur de skulle ta ärendet vidare. Studien är begränsad till den tekniska biten, där bland annat val av utrustning, trådlösa tekniker och riskanalys av nätverket ingår. Arbetet varit väldigt teoretiskt inriktat med en metod som till största del består utav att samla information och kunskaper från vetenskapliga rapporter, teknikorienterade hemsidor och andra relaterade arbeten.De trådlösa standarder som jämfördes teoretiskt i förstudien var 802.11g och 802.11n. 802.11n valdes som den standarden som bäst passade just detta nätverk, främst för dess positiva egenskaper när det gäller täckning, hastighet och bakåtkompatibilitet. 802.11n seräven ut att garantera en säker framtid när det gäller implementering i mobila enheter. Föreslaget på utrustning består av två olika accesspunkter, antingen 2602e eller 3602e beroende på den slutgiltiga budgeten. Dessa produkter är från Cisco och klarade olikastresstester med bra resultat samtidigt som de stödde den föreslagna standarden 802.11n. WLAN controllern (Ciscos 5500-serie) som valdes ut stödjer det krav på antal accesspunkter som bestämts, samtidigt som den lämpar sig bra för eventuella framtidakrav. Routern till detta nätverk är en Cisco 891-router. Anledningen till att denna router valdes var för att den har 4 portar som kan ge ström över Ethernet till accesspunkterna. Säkerhetsanalysen gjordes med hjälp utav CORAS-metoden där det diskuteras vilka riskernätverket kan ställas inför och vad dessa risker kan få för konsekvenser. Försök till att hitta lösningar som var direkt applicerbara på det stadstäckande öppna nätverket gjordes även.Förstudien avslutas med en kostnadsberäkning av nätverket, baserad på andras tidigare arbeten och deras kostnader, speciellt från Jönköping, Helsingborg och Mountain View.

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  • 105.
    Bennulf, Mattias
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production Systems.
    Identification of resources and parts in a Plug and Produce system using OPC UA2019In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 38, p. 858-865Article in journal (Refereed)
    Abstract [en]

    This paper describes a method together with an implementation for automating the detection, identification and configuration of newly added resources and parts in a Plug and Produce system using OPC UA. In a Plug and Produce system, resources and parts are usually controlled by agents, forming a multi-agent system of collaborating resources. Hence, when a resource or part is connected to the system, a corresponding agent must be instantiated and associated with that specific device. In order to automate this, the system needs information about newly connected devices. This information could, for example, be positional data describing where the device is connected. Some devices like tools and parts to be processed have no own network connection, but still, they should get an agent with correct configuration instantiated. In this work, OPC UA is used for communication between devices and the corresponding agents. All agents and their communication are handled by an Agent Handling System, consisting of an OPC UA HUB together with functions for device detection and agent instantiation. The HUB is used for transferring data between devices and their agents in the network by OPC UA protocols. When a device is connected to the network, it is detected, and a connection is automatically created to the HUB that becomes configured for transmitting data between the device and its corresponding agent. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

  • 106.
    Bennulf, Mattias
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Svedman, Jacob
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Automatiserat hem: med gränssnitt för anslutning av utrustning2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim is to find out how to develop a system for automated homes, where users can eas-ily connect custom built equipment. An example would be controlling a sprinkler or meas-uring wind speed. It should also be possible to develop more advanced accessories.

    To create a system that meets this, the system must have a central system to coordinate de-vices and data. We also need an open interface for communication between the central and the user devices. One should replace direct change in code and database center to instead create graphical interface to the users, it makes it easier for them to learn the system. One should not, however, restrict user freedom to develop units, more than the functionality of the interface and the center's configuration options. Parts of the requirements was imple-mented in a prototype, to confirm that the system works in reality. The prototype is based on a server with Debian as central in the home. For example, it can take a decision whether the alarm will go off or if a lamp should light. The user should easily be able to give in-structions to the central and reprogram how it should behave. Users can develop their own equipment and then simply connect it to the central and configure it via various web-based tools. In this way, accessories are created and connected without changing anything on the server more than the contents of the database. To test the system we created a modular house that is two walls in a cross, where equipment and central system are placed. Since power and lock bolt where used, this resulted in that some disruption where noticed and removed

  • 107.
    Bennulf, Mattias
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    Verification and deployment of automatically generated robot programs used in prefabrication of house walls2018In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 72, p. 272-276Article in journal (Refereed)
    Abstract [en]

    This paper presents a method for automating the generation, verification and deployment of robot programs used in prefabrication of walls for family houses. The making of robot programs is today performed manually by experts, i.e. implying high costs. This is a huge disadvantage since each wall can be unique. The work demonstrates, with implementation and testing, a method to automate the generation of robot programs for fabrication of walls made of wood. This includes the task of generating collision free paths, automatic verification of path performance and deploying to a real industrial robot with minimal human interaction. © 2018 The Authors. Published by Elsevier B.V.

  • 108.
    Berg, Gustaf
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Brattlöf, Magnus
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Distributed Checkpointing with Docker Containers in High Performance Computing2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Lightweight container virtualization has gained widespread adoption in recent years after updates to namespace and cgroups features in the Linux kernel. At the same time the Industrial High Performance community suffers from expensive licensing costs that could be managed with virtualization. To demonstrate that Docker could be used for suspending distributed containers with parallel processes, experiments were designed to find out if the experimental checkpoint feature is ready for this community. We run the well-known NAS Parallel Benchmark (NPB) inside containers spread over two systems under test to prove this concept. Then, pausing containers and unpausing them in different sequence orders we were able resume the benchmark. After that, we further demonstrate that if you carefully consider the order in which you Checkpoint/Restore containers, then the checkpoint feature is also able to resume the benchmark successfully. Finally, the concept of restoring distributed containers, running the benchmark, on a different system from where it started was proven to be working with a high success rate. Our tests demonstrate the performance, possibilities and flexibilities of Dockers future in the industrial HPC community. This might very well tip the community over to running their simulations and virtual engineering-applications inside containers instead of running them on native hardware.

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  • 109.
    Berg, Gustaf
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Larsson, Daniel
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    En jämförande studie av tekniker för trådlös platsanalys vid Universeum2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis a comparison between a predictive site survey and two passive site surveys is performed, to see if only a predictive survey is enough to estimate a well-functioning wireless network. Some fundamental facts and techniques that are involved in wireless networks are presented and also the method of how the site surveys were planned and performed. The outcome is compiled in diagrams. The difference between a predictive and a passive site survey is analyzed, and shows if the prediction is trustworthy or needs to be verified.

  • 110.
    Berggren, Andreas
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Bengtsson, Oscar
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Implementering av 802.1X i en kommuns nätverk2022Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    The work explains what 802.1X is and how it can be applied in the municipality's network. It goes through which protocols are used as well as how the different units communicate with each other. Configuration and tests are done according to requirements specification and are reviewed to confirm the function.

  • 111.
    Bergkvist, Sofia
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Runge, Johanna
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Allmänna och enskilda vägar: Väghållaransvar utanför detaljplanelagt område2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In terms of traffic, in order for the infrastructure to work it requires that the road network fulfills its function. Communication between the different parties, the Swedish Transport Administration (Trafikverket), municipalities and individual property owners is important, and situations with conflicts and disagreement are easy to evolve. Which part should manage the operation and maintenance to a certain road and what the laws say about each road are sometimes unclear. The Swedish Transport Administration, municipalities and individual property owners are the three different parties that can be responsible for operation and maintenance, also known as road holders, by roads. If the road is located within or outside of the planned area depends on which legislation is applicable. Planning and building act (PBL) and road legislation (VägL) are the laws used inside the planned area, but so is the plant legislation (AL) in the formation of community facilities. It is mainly the planning and building act that is applied because it regulates the planning, the road is then named street according to PBL, but in some cases the municipalities may choose to plan the road according to the road legislation. In cases where the road legislation is applied the process is more extensive and for this law to apply, the roads must be public. Outside planned area there is no law that regulates in the same way as the planning and building act, instead the plant legislation is applied for the individual roads mainly to establish a community facility. It is at the establishment of the community facilities the statutes are set, these regulate the operation and maintenance of the road which concerns the individual property owners. The study includes a survey conducted to 49 municipalities in the county Västra Götaland. Four of these municipalities were then selected for a further interview. The Swedish Transport Administration and National federation individual roads (Riksförbundet enskilda vägar) were also interviewed, this in order to get an overall view and not only information from different municipalities.The result is based primarily on the interviews but also the answers from the survey. The information that emerged from the interviews with the municipalities differs from the answers received from the survey whether the municipalities experience problems with managing individual roads. Instead, the municipalities mean that there are generally more problems in the planned area than outside. The result also indicates a variation between the municipalities, while the Swedish Transport Administration has clear limits on the selection of road holders. REV addresses the problem of the difficulty of getting people to arrange  ii Allmänna och enskilda vägar – Väghållaransvar utanför detaljplanelagt område  the board work on an individual road. The definition of public and individual road differs between the different interviewed parties. The study reflects on distinct guidelines for when a road should be public respectively individual in order to clarify the boundary of when road maintenance takes over and another ends.

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  • 112.
    Bergstrand, Andrea
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Säkerhetsbilden mot den uppkopplade bilen: En analys om säkerhet och hot i fordons trådlösa kommunikation2019Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Connected vehicles are being developed extensively, and in 2019, vehicle manufacturers and transport companies will start equipping vehicles and roads with wireless communication around Europe. This will increase safety and streamline the traffic by allowing drivers to be warned of what they have not yet seen as vehicles around the corner, queuing, slipping, collision and road work. However, accidents involving connected vehicles have occurred recently, which has created uncertainty regarding its safety. Great demands are placed on its safety when connected vehicles will increase significantly on the roads.

    The study aims to carry out a safety assessment against the connected car with the aim of investigating potential threats and risks in vehicle wireless communication, what is required for the technology to be considered safe and reviewing various safety solutions developed.

  • 113.
    Bernard, Prabhu
    University West, Department of Engineering Science.
    Study of vector control strategy on Interior Permanent Magnet Synchronous Motors2023Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis presents a comprehensive study of Direct Torque Control (DTC) for Interior Permanent Magnet Synchronous Motors (IPMSMs) evaluating its potential in high performance motor drive systems. The research begins with a literature review, looking into the fundamental principles of DTC, Pulse Width Modulation (PWM), Space Vector Modulation (SVM) and Field Oriented Control (FOC).

    The methodology section involves the detailed modeling of IPMSM using Simulink for a precise representation of system dynamics. The Park and Clarke transformations are employed in the phase transformation of currents and voltages to simplify the control strategy. The implementation of Voltage Source Inverter (VSI) is explored and its crucial role in modulating input signals is discussed. Subsequently, the implementation of DTC is demonstrated, capturing the key focus of the thesis.

    The validation stage verifies the model created in Simulink against research papers published in the same field. This is coupled with an analysis of sector selection and switching table in enhancing DTC performance. The results and conclusion reassess the voltage and flux vectors, evaluating their influence on the system. Additionally, the effectiveness of Proportional-Integral (PI) control for maintaining the desired speed and torque is analyzed.

    Thus, this thesis offers a holistic perspective on the implementation and performance of DTC for IPMSMs, contributing to the existing body of knowledge and paving the way for future research in this field.

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  • 114.
    Berndtsson, Jesper
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    By, Mathias
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Analyzing and improving a wireless network2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is about how a site survey is carried out using software and how a site survey can collect the information needed to improve the existing wireless networks. The report provides both general information about wireless networks and practical examples with authentic measurements in the corporate environment.

    Problems can arise in a wireless network if the planning is not properly done. A measurement have been made in second floor, where company X is located.

    The results of the survey is presented in images that show the strength of Company X wireless networks, on the second floor. Images also shows noise, overlapping channels and how the signal strength related to these.

  • 115.
    Berndtsson, Jesper
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    By, Mathias
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Analyzing and improving a wireless network2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is about how a site survey is carried out using software and how a site survey can collect the information needed to improve the existing wireless networks. The report provides both general information about wireless networks and practical examples with authentic measurements in the corporate environment.

    Problems can arise in a wireless network if the planning is not properly done. A measurement have been made in second floor, where company X is located.

    The results of the survey is presented in images that show the strength of Company X wireless networks, on the second floor. Images also shows noise, overlapping channels and how the signal strength related to these.

  • 116.
    Besic, Haris
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Elbilsladdning för villaägare2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    For several years, the transport sector has been dominated by fossil fuels that have a negative impact on the environment. In recent years, vehicles powered by electricity have increased and this has led to more and more people needing to know more about charging for these electric cars, especially charged hybrids and clean electric cars. The most common in Swedish households today are plug-in hybrids, which is a car that is powered by both an electric motor and a conventional internal combustion engine. As the number of electric cars has increased a lot in recent years, there are many challenges that need to be clarified and the report focuses on one of these areas that is charging for homeowners. Why the report focuses on charging for homeowners is because several electric car owners choose to still charge from the regular wall socket, and this leads to an increased risk of accidents. The report provides an insight into the dangers that arise when charging from a standard wall socket and then the report provides a safer alternative for charging that is via a charging box. The report also deals with different types of standards, rules, and general information about electric car charging. The report also provides an insight into what it might look like in the future for electric car charging. That functions that make charging safer in today's situation that are only available with the help of cable or charging box will instead be present in the car. Functions such as power selection, load balancing and other things will also be available in future electric cars. Furthermore, the report examines the different charging options that exist today for homeowners and draws up two scenarios. The first scenario through the standard wall socket and one with the help of a charging box. Risks and costs are discussed to then make a recommendation of what is to be considered in the various scenarios. Following a market and risk overview, the currently best alternative is to invest in a charging box that is approved for the climate step contribution. If a charging box is approved for the climate step, basic functions that are important will be included.

  • 117.
    Beyrouti, Magdalena
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Larsson, Patrik
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Beredning av landsbygdsnät Restenäs-Andorra i Uddevalla kommun2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is about how preparation work is accomplished by contracts and permit search to network planning and dimensions. The requirement for reliable electric power increases because electricity is such an important part of our society. Large disruptions cause significant costs for electric distribution companies and customers. . To increase reliability and make the power grid weather secured, overhead lines are replaced with underground power cable.

    The preparation work is preformed to weatherproof the electric power grid in Restenäs-Andorra outside Ljungskile in the municipality of Uddevalla, by placing power cable in the ground instead of overhead power lines. The project will be implemented in connection with the development of communal water and sewer to reduce the cost of excavation.

    The result of this preparation work includes a new 10/0,4 kV substation, four cable boxes together with 1200 m of high voltage power cable and 800 m of low voltage power cable. The electric transmission network has been placed in the same excavation as water and sewer as long as possible. The substation and cable boxes are placed for easy access and to create a good mesh. A P2-calculation has been created to get an overview of the costs of the project.

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  • 118.
    Beyrouti, Samer
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Yaghoubipoor, Mohammad
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Standardisering av reläskåp för transformatorstationer2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The thesis is a case study about standardization of a relay cabinet at E.ON´s 55/11 kV substation. Standardization of the relay cabinet implies that a solution is developed from a station and applied to other stations with the same conditions. Prior to the development of the relay cabinet, a basic theoretical study was performed about the external and internal faults that a transformer may be exposed to and the most common transformer protection philosophies were investigated. In addition to relays other components in the relay cabinet were also examined. The project was then divided into parts where control of the assigned data and circuit diagrams were performed. The material consists mainly of connection charts and circuit diagrams that describe the station and cabinet construction and the components used at present. The charts for the existing devices in the relay cabinet were examined extensively. In combination with E.ON's requirement for the cabinet components and the transformer station the components technical specifications as well as the protection functions were established. A request for quotation was sent to the leading manufacturers with the component's technical specifications. The answers provided by the suppliers were analyzed and then compared with the existing ones. A request was also sent to relay cabinet installation companies. Only one company was able to perform the work. All data was then compiled and analyzed. Following the study of the market leading manufacturers relay D, voltage regulator F and annunciation relay H were chosen as the best recommended components. Other products that have some advantages are analyzed and discussed in the report. The only installation company that responded was chosen to perform the installation work.

  • 119.
    Bhat, Achintya
    University West, Department of Engineering Science.
    Precise Robot Navigation using Machine Vision Techniques: Estimating the camera position by using machine vision and photogrammetry techniques on an image2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The concept of Automation began with the rise of Industrial Revolution 3.0. Automation was then done in a partial manner with help of computers and programmable controls. With Industrial Revolution 4.0, world started focusing on automation. Industries working on automating their factories and car manufacturers towards driverless cars. Nowadays, robots are being used for public services and transportation. For navigation purpose, these robots arestill using Global Positioning System (GPS), which is highly advanced but with its own uncertainties. To bypass the use of GPS in industry and implementation in autonomous cars, one can use combination of machine vision and photogrammetry techniques. The machine vision aspect is to detect multiple objects having known coordinates in wall coordinate system and identify the position of these objects by recognising their class value in an image. First step was to calibrate the camera being used for the work. It was done by using MATLAB’s inbuilt Camera Calibrator App, from where we derive the focal length of the camera. Next step was to detect and classify the objects present in the environment. After detection, the centroid values of each object in the image plane were determined. For the photogrammetry aspect, one should know these objects’ position in wall coordinate system, and then using the concept of collinearity and triangulation, combining it with the centroid values gained from machine vision aspect, one estimates the position of camera from which the video and images are being taken. The result of this part indicates a method where the camera can detect multiple objects in the image going from minimum of four to maximum of five with their centroid values and respective classes plotted on the image or the frames of the video. As the distance between the image and the projection centre is just the focal length of the camera, the method utilises the knowledge of basic trigonometry to determine angles between the projection centre of the camera and object coordinates in image and the angles are observed to be same for projection centre and actual objects in the environment. From the calculated distances between the objects in real time and the projection centre, one estimates the coordinate of the projection centre using a nonlinear least squares method. All these calculated values combined with the data gathered from the machine vision aspect, are used to estimate the camera position in an environment with some uncertainty. This uncertainty is the error in calculating the position of the camera. The result shows the proof of conceptual model and can be implemented by industries to overcome the issues faced with the use of GPS. 

  • 120.
    Bheemavarapu, Naga Sudha
    University West, Department of Engineering Science.
    Model building and comparison between the combined model and discrete event model2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    By conceptually comparing the two simulation methods, this thesis work investigates the limitations and possibilities of DES and combined model in plant simulation and visual components. Also look into which methods are best for teaching simulation and how they affect learning outcomes. A common benchmark was created to compare the DES and combined model, and a focus group session was held at University West to gather information from participants about the model's limitations and possibilities. Using an combined model instead of a DES model solves complex problems, while a hybrid approach allows existing models to be flexibly combined within a common large-scale context. According to the focus group, plant simulation is used to quickly build a conceptual model; however, one of the most concerning limitations of plant simulation is rarely close to real time application. Visual components, on the other hand, are the inverse of plant simulation; the models that are built arerelated to real-time applications, and the most significant disadvantage of visual componentsis time consuming

  • 121.
    Bidlis, Niar
    et al.
    University West, Department of Engineering Science.
    Rezai, Zahed
    University West, Department of Engineering Science.
    Övervakning av litium-jon batterier i lager2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This work focuses on the development of a system to accurately monitor the state of charge of lithium-ion batteries, aiming to prevent discharge and potential damage during storage. By using this system, the lifespan of the batteries can be extended, and more sustainable and efficient energy management can be achieved. Identifying issues and deviations in battery cells in real-time during storage allows for prompt actions to minimize the risk of damage, thereby improving performance and increasing the battery’s lifespan. Ensuring the safe and sustainable operation of battery-powered systems, this work contributes to a more efficient utilization of resources. In this study, a system is developed to continuously monitor the state of charge of an individual cell, ensuring it is not excessively discharged and damaged. The system also performs capacity tests to assess the battery’s health condition. Additionally, the system ensures that the charging state of the batteries is maintained within recommended levels to enhance their lifespan and performance. Initially, a Simulink model was created for this purpose, and based on the Simulink model, a real-time battery monitoring system is built, capable of performing capacity tests whennecessary. The results were successful and met all the expectations of the authors. The system continuously monitors the cell by reading its voltage and gathering information about its charging state. It also performs capacity tests, yielding positive results. Better component selection could have been done to optimize and enhance the system’s accuracy in calculations. The main limitations encountered were related to the constraints of the Arduino Uno, such as limited memory and voltage reading inaccuracies. In conclusion, the authors have achieved their desired goals with this project and recognize that the demand for such systems will significantly increase as society moves toward electrification.

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  • 122.
    Birgersson, Patrik
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Svensson, Martin
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Utvärdering av möjligheter för semiautomatisk reläskyddsprovning med Omicron CMC 3562017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When energy companies undertake the maintenance responsibility for their power plants and facilities the protection systems may be tested by different contractors. As a result, the testing procedures may differ between facilities. In order to achieve a more similar testing of the protection relays they should be tested the same way every time. Testing of relays are usually performed by experienced personnel that may employ in slightly different ways of testing due to the lack of one which is standardized. This leads to a situation where the knowledge within this area of work stays in the minds of only a few employees of the company.

    The reason for this project to be made is the employers wishes to investigate if the testing of relays can be performed in a more similar way in order to achieve comparable results and to minimize the risk of mistakes made during the testing.

    With Omicron CMC 356 and the associated software "Test Universe 3.10" it is possible to program tests in advance and bring to the station and implement the prepared tests. This report is performed as a pilot project to show the client how the tests can be programmed and how Omicron might be implemented in the maintenance testing of their relay protection.

    The report begins with a theoretical review of the functions that the thesis comprises. The construction of the relay with the principles it uses are explored, the limits and accuracy for the measurements are also reviewed. The thesis is because of time constraints limited to testing the functions: overcurrent, overvoltage, undervoltage, underimpedance, as well as differential and frequency protection. The thesis also contains a practical part in which testing of the relays was completed in a hydropower plant. Omicron CMC356 was the testing equipment used along with the related software "Test Universe 3.10", where the testing functions were programmed. The modules used for testing the relay functions are described along with the essential parts needed to test the functions that the thesis comprises.

    The conclusion of the thesis is that several of the functions needed can be performed automatically. A decision has to be made about the balance between economy and quality because of the initial work that have to be made to program every station that is meant to be tested in this way.

  • 123.
    Bislimi, Agon
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Planering av elbilsladdning för bostadsfastigheten Skördetröskan 1, Trollhättan.2021Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The climate goal can only be achieved by reducing carbon dioxide emissions. To do this, a transition from fossil-fueled vehicles to electrificiation of vehicles must take place. This has led to vehicles manufactures switching to producing more electric cars or plug-in hybrids, and production of electric cars has increased significantly during the year between 2015 and 2020. The report examines possibilities for installing charging stations in the car park at the residential property Skördetröskan 1, Trollhättan. The car park will have space for six cars to be charged with 3 charging boxes with double sockets of 22 kW. Type-2 connectors with semi-fast charging will be equipped. Load balancing must also be installed and will give a reduced total power of 40 kW instead of 66 kW if it were not included. But with the help of the dynamic load balancer, the entire system is protected from overload. In connection with the installation, a 0.6/1.0 kW low-voltage cable must be used by the NV1VV-R model. Which is fused with a 35 A fuse. 

    An estimation of the cost of the project is described in the report with different price and alternatives at repayment period. One repayment period is 8,1 years and the other is 5,4 years. Why there will be different times is due to the fact that in a calculation, the investment support has been included. Which has led to a shorter repayment period. 15 000 SEK per charging box is the investment support from the Swedish government. A total of 45 000 SEK for this project. Revenues vary depending on how long and often the customer charges their electric car.

    An estimated calculation has been performed on this calculation. The feasibility study is based on an estimated assumption and in the case of an efficient and profitable project, according to the author, a deeper insight and analysis as well as evaluation of suppliers is required. 

  • 124.
    Bittar, Sadik
    University West, School of Business, Economics and IT, Divison of Informatics.
    Collaborative Learning in a Learning Management System: A Qualitative Case Study of Work-Integrated E-Learning2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    With the increase in importance of a collaborative learning approach in the era of web 2.0 and the emergence of the social web, designing a convenient and adaptable LMS that can support this approach is becoming more challenging. This thesis has been conducted as a qualitative case study. The case study is represented by the "ProdEx" project in the Production Technology Center (PTC) at University West. This project focuses on collaboration and sharing knowledge between academia and industry, by offering Work Integrated e-Learning courses at university level to manufacturing industry companies. Within this environment, the aim of my study was to examine collaborative learning phenomena within an e-WIL environment. The research question of the study was: How does tailored LMS affect collaborative learning in an e-WIL course?

    To answer this research question, I used interviews as the main research method to collect the empirical data. Thus, I conducted seven interviews with different stakeholders in the project, including the project coordinator, a professor who teaches advanced level courses, and one participant of the professor's courses. Moreover, I used an open-ended questionnaire to collect data from the former participants who couldn't attend face-to-face meetings. All the interviews have been transcribed and analyzed using content analysis method.

    During the course of the research, a need to design a prototype artifact, i.e. a WordPress-LMS, arose. The purpose was to put the new collaborative features and the professor's requirements to the test in one of his e-WIL courses, "FEM1". I used the participatory design method to design the prototype with the professor, mainly because he is the primary user of the platform and has particular requirements of the system supporting his e-WIL courses.

    The requirements are derived from his highly pedagogical and technological course demands.The theoretical framework of this study contains a sociocultural theory used to conceptualize the research. The literature of sociocultural theory and the studied phenomena, together with the empirical results, enabled me to answer the research question and draw the following conclusion, namely that the designed LMS can influence the collaborative learning phenomena by enabling collaborative features in the LMS and sustaining the practice community built through it, while t at the same time, enabling the implementation of e-WIL courses, expanding the audience of participants and maintaining the learning relationship with the e-WIL courses. The designed LMS achieves the above through the features implemented in it. These features have been designed, built and customized to adapt the particular situation of the professor, and to suit his high pedagogical and technological course demands.

  • 125.
    Bjernstrand, Carl
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Förstudie inför uppförande av laddstationer för elbilar på personalparkering2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In recent years electric cars has increased in numbers, this increase is expected to continue in the coming years. With an increasing number of electric cars, more charging stations are required. Arctic paper Munkedals AB intends to construct charging stations for charging electric cars, primarily for visitors to the factory. There are several parking spaces for employees located next to the factory, and one parking space for visitors. Approximately 120 of the parking lots for the employees has access to sockets for block heaters. To reduce the investment cost, it is beneficial to connect the intended charging stations to the existing installation for the block heaters. The pilot study includes a compilation of data for the existing installation of the block heaters. Based on the compiled data the maximum current load for the existing cables has been calculated, the result of the calculations shows that in 2 centrals it is possible to switch to a higher fuse. The report explains generally about how electric cars and charging stations work. Products from a selection of suppliers that are considered relevant for this work, are described. Solutions and costs have been developed based upon 2 scenarios, where either the existing centrals for block heaters is replaced with charging stations or remains according to current version. The solutions are covered by the parking space next to the 40kV switchgear and a charging station on the parking lots for visitors. Essential for both solutions are the load balancing system, which enables a larger number of charging stations that otherwise wouldn’t be possible regarding to the dimensions of the existing installation. Of the 2 reported alternatives for the construction of charging stations, alternative 2 where the existing block heaters are replaced with charging stations are considered most suitable to proceed with. With this alternative 15 charging stations can be installed to a total cost of approx. 525 kkr. Because of the scalability of the solution, it is recommended to make the installation of the charging stations in stages as the need arises. This means that statistics for the charging stations can be compiled and analyzed to provide a good basis for further expansion. By carrying out the expansion in stages, the total cost will be distributed over time. Initially this means the construction of 1 charging station for visitors to a cost of approx. 110 kkr.

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  • 126.
    Björnberg, Max
    et al.
    University West, Department of Engineering Science.
    Dellsjö, Nicklas
    University West, Department of Engineering Science.
    Frekvenshållande stödtjänster från vindkraftsparker2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Electricity production in the Swedish power grid system has during recent years experienced a major change where there has been a large-scale expansion in renewable electricity production. This have brought significant challenges to the Swedish power system, to be able to maintain a stable power system, a great need for frequency regulation is required. The thesis is carried out in collaboration with Rabbalshede Kraft and will investigate the profitability of three cases of frequency regulation, using differing power sources, from an existing wind farm that supplies the frequency maintaining reserve FCR. The report’s focus is examining the financial profit for the various cases based on historical data from the years 2021 and 2022. The three cases investigated in this thesis is frequency regulation with only the wind farm, frequency regulation with a battery plant that has the same connection point as the wind farm, and a combination of these, where the wind farm supplies FCR-D Down and the battery plant FCR-D Up. To determine the profitability, a calculation model was developed as well as a bid strategy and frequency data processing program. The model is based on historical data from market prices, frequency data and production data from the wind farm. The bidding strategy for FCR-D with the battery facility is conservative as recovery of the battery takes place every two hours instead of delivering the service every hour without recovery, which is likely possible. However, this possibility is not investigated in this report and therefore, a conservative strategi is used to ensure the fulfilment of the conditions of delivering the service. This strategy leads to a halved approximated profit. The bid size for the wind farm is set to 5% of the instantaneous output for the hour of operation. For the cases investigated, the profitability varies depending on the support service delivered and the payback period for the battery plant. The best results for the different cases are as follows for 2022:

    • Case 1-Frequency regulation with only the wind farm: FCR-Down 1.52 MSEK

    • Case 2-Frequency regulation with only battery system: FCR-D Up 2.92 MSEK, 2-year payback period.

    • Case 3-Frequency regulation combination: FCR-D Down and FCR-D Up 4.44 MSEK.

    This study’s most profitable result is obtained with Case 3 where a combination of the wind farm and the battery plant is used. To start delivery of support services, it is required that the wind farm and battery facility go through a pre-qualification test.

  • 127.
    Björnklint Assia, Tony
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Nyman, Alfred
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Elsystemet och dess utmaningar i ett framtida Sverige2021Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden is facing an energy transition in both electricity production and consumption. Based on the Paris Agreement and Agenda 2030, Sweden aims to be climate neutral by 2045. This means major challenges for the electric power industry. Industries want to electrify their operations and the introduction of electric vehicles in the transport sector is fast. Increased electricity use and growing problems with capacity constraints are some of the challenges that the electricity system of the future will have to deal with.

    The report aims to provide an idea of what the electricity system of the future may look like. The aim is also to attract future and new engineers to the electric power industry by maintaining a high readability. It describes national and international climate goals, how the Swedish electricity system works today and a survey of current permit processes for new construction of electrical infrastructure and electricity production facilities. Also what challenges the Swedish electricity system faces with e.g. lack of capacity and the need for expansion.

    In the picture of Sweden's future electricity system that has been produced, three electricity production scenarios are examined which, through different electricity production mixes, can supply Sweden with the forecasted electricity demand of 240 TWh/year. One scenario where nuclear power remains to the same extent as today and two scenarios without nuclear power where electricity production is instead is replaced by solar power and offshore wind power, respectively. In all three scenarios, land-based wind power is expected to be significantly expanded. The Swedish future electricity system will probably not reflect any of these scenarios, but rather a combination of them. The types of power that have the potential to be expanded will need to increase to achieve the goals.

    With highly variable electricity production in the electricity system, new challenges arise. The balance between electricity production and electricity consumption must remain. The balancing will be made by flexible production, energy storage and demand flexibility. 

    The report states that Sweden has good prospects of becoming the world's first fossil - free welfare nation. However, this presupposes that the permit processes are streamlined, and political decisions enable a rapid expansion of the electricity grid and fossil-free electricity production.

  • 128.
    Bodestål, Emil
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Jakobsson, Daiel
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Metoder för att minska risken för sympati-utlösning av Vattenfalls transformatorstationer2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This Bachelor's Thesis has been produced in cooperation with Vattenfall Eldistribution AB. In the center of operations in Trollhättan, they manage their electric grid in Sweden. During the energizing process of a transformer in parallel with another one in use, the station sometimes becomes disconnected. This phenomenon is called "sympathetic disconnection". It occurs in some way randomly and is fairly uncommon. At Vattenfall it occurs a couple of times every year. This means that there are few cases to study and therefore most of the project is based upon interviews and one well-documented case. Based on that case, a computer model was created in PSCAD EMTDC and modified to create a situation where the phenomenon always occurs.

    The goal for this project was to find some strategies and test those in PSCAD to see if they would make the situation better. The different types of strategies tested are to change the point of circuit-breaker operation, the tap changer, an alternative energizing from the secondary side, different winding connections and the significance of a strong network. A theoretical analysis of the importance of an inrush limiting resistor and synchronized switching was also made.

    The results show that the time of the circuit-breaker operation is of great importance. With support of synchronized switching an energizing can be done completely without affecting the feeding grid, nor the parallel transformer. Individual breakers seems to be worse than just sensing the voltage zero crossing and operating all the breakers simultaneously. The simulations have shown that some measures can improve the chances of a successful energizing. The tap-changer should be set in the position with the largest ratio. A wye-delta connected transformer is better than a wye-wye connected, which is the standard at Vattenfall. It is also standard to energize transformers from the primary side. Simulations have shown that an energizing from the secondary side would result in several benefits. At last, a strong network is preferred.

    The earth-fault protection relay in the feeding line is most prone to cause a disconnection. Therefore, depending on the situation, a change in the time setting in the relay's fourth step should be considered.

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  • 129.
    Boklund, Andreas
    et al.
    University West, Department of Technology, Mathematics and Computer Science, Division for Computer Science.
    Namaki, Nima
    University West, Department of Technology, Mathematics and Computer Science, Division for Computer Science.
    Mankefors-Christiernin, Stefan
    University West, Department of Technology, Mathematics and Computer Science, Division for Computer Science.
    Jiresjö, Christian
    University West, School of Business, Economics and IT, Division of Computer Science and Informatics.
    A characterisation tool for the impact of network deficiencies on HPC applications2008In: Proceedings of the 2008 International Conference on Parallel and Distributed Processing Techniques and Applications, PDPTA 2008, 2008, p. 888-894Conference paper (Other academic)
  • 130.
    Bolander, Ola
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Erving, Ivar
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Elkvalitetsundersökning vid Sahlgrenska sjukhuset2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    On behalf of ÅF Consult an electrical power analysis has been made for Västfastigheter at a switchgear at Sahlgrenska University hospital in Gothenburg. The intention is primarily to investigate the data of most interest to the customer such as variations in voltage, imbalance in supply voltage, voltage harmonics, power consumption and neutral conductor current. In addition, Västfastigheter have requested an investigation of a vibrating busbar trunking supplied from the switchgear. The starting point of thesis work is a theoretical background described in the first part of the work and the goal is to deliver a good basic understanding of the concept of power quality.

    Measurements have been carried out both when the system was fed from the normal supply as well as during a 6 hours long test of the backup power supply system. The result at normal supply showed, according to current regulations, that all parameters are approved except for harmonics number 9 and 15 for which to high levels are detected. When the load was fed from the backup power supply the results show no significant changes compared when the load was fed from the normal power supply. However, some noticeable phenomena linked to the voltage and the current waveforms are noted. They are of interest for getting a deeper understanding of the different supply modes. In backup supply mode the grid impedance increases, this is normally described as the grid becoming weaker. This is shown as increased imbalance between the voltage levels of the three phases. It is also characterized as the current distortion having a greater impact on the waveform of the voltage leading to a larger level of voltage distortion compared to normal supply.

    The connected load on the vibrating busbar trunking is examined with a power quality analyzer and vibrations are measured by an accelerometer. Since the degree of the vibration decreases as the electrical power is unloaded throughout the different levels at Sahlgrenska, the theory is that they are related to the level of the current. To further strengthen this theory reference can be made to two adjacent busbar trunking of the same type that are considerably less loaded. They have noticeable vibrations but with a much lower magnitude, which is comparable with how the investigated vibrating busbar trunking behaves further out.

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  • 131.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Reconfigurable and Flexible Industrial Robot Systems2014In: Advances in Robotics & Automation, E-ISSN 2168-9695, Vol. 3, p. 117-Article, review/survey (Other academic)
    Abstract [en]

    This paper presents a concept for reconfigurable and flexible robot systems. To reach a technology readiness level where solutions and results can be implemented in industry, the focus in this work is on systems with limited number of robots, and work scenarios which are reasonable complex but hard to automate using standard solutions.Four distinct areas have been identified as important within the concept and further studies: (i) human machine interaction, (ii) safety including collaboration, (iii) programming and deployment, and (iv) planning and scheduling. Feasibility studies have been made which addressed issues (ii) and (iii), in scenarios with collaboration between robot and human, or between two robots. For the chosen work scenario, manufacturing of structures in wood for family houses, challenges related to programming and safety was identified and possible solutions outlined.The concept and the studies indicate that feasible solutions can be found and designed given a reasonable consistent work processes and products. In this study, the processes are similar, nailing and screwing but different sizes may apply, the material is similar but variations may apply, and the construction is different of each product, but include the same type of operations at different locations. Our study confirm that human collaboration improves the ability to implement and use robots as it make it possible to move some operations to the human which otherwise would add to the complexity of the system. Furthermore, programming can also I general be simplified although methods for automatic programming has been tried out. But in some cases, the solution space is limited and the ability to move certain operations to a human simplifies the programming task. However, further work needs to be done in this area specifically related to safety issues for safe collaboration.

  • 132.
    Bolmsjö, Gunnar
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Bennulf, Mattias
    University West, Department of Engineering Science, Division of Production Systems.
    Zhang, Xiaoxiao
    University West, Department of Engineering Science, Division of Production Systems.
    Safety System for Industrial Robots to Support Collaboration2016In: Advances in Ergonomics of Manufacturing: Managing the Enterprise of the Future. Proceedings of the AHFE 2016 International Conference on Human Aspects of Advanced Manufacturing, July 27-31, 2016, Walt Disney World®, Florida, USA / [ed] Christopher Schlick, Stefan Trzcieliński, Springer International Publishing , 2016, p. 253-265Chapter in book (Refereed)
    Abstract [en]

    The ongoing trend towards manufacturing of customized products generates an increased demand on highly efficient work methods to manage product variants through flexible automation. Adopting robots for automation is not always feasible in low batch production. However, the combination of humans together with robots performing tasks in collaboration provides a complementary mix of skill and creativity of humans, and precision and strength of robots which support flexible production in small series down to one-off production. Through this, collaboration can be used with implications on reconfiguration and production. In this paper, the focus and study is on designing safety for efficient collaboration operator—robot in selected work task scenarios. The recently published ISO/TS 15066:2016 describing collaboration between operator and robot is in this context an important document for development and implementation of robotic systems designed for collaboration between operator and robot.

  • 133.
    Bolmsjö, Gunnar
    et al.
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Collaborative Robots to Support Flexible Operation in a Manufacturing System2012In: Flexible Automation and Intelligent Manufacturing, FAIM 2012 / [ed] Hasse Nylund, Satu Kantti, Ville Toivonen, Seppo Torvinen, Tampere University, Finland, 2012, p. 531-538Conference paper (Refereed)
    Abstract [en]

    Collaborative robotic systems where human(s) and robot(s) cooperate in performing a common task is an attractive solution to introduce automation combined with high flexibility for tasks that have a high complexity and characterized by low volume or down to one-off. By introducing collaboration in robotics systems, the operator can complement with cognitive capacity and skill in order to gain in flexibility and agility in the task operation. This paper describes on-going work related to work on collaboration between operator and robot. User scenarios are outlined together with methods, software components and hardware to support collaboration, where some of these are under development. As the standards related to collaborative robotic systems are soon to be completed, it is expected that this type of semi-automatic systems will be important for flexible and agile automation of production which otherwise cannot be automated.

  • 134.
    Bonilla Hernández, Ana Esther
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Beno, Tomas
    University West, Department of Engineering Science, Division of Production Engineering. University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Repo, Jari
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Wretland, Anders
    GKN Aerospace Engine Systems AB, Trollhättan, Sweden.
    Analysis of Tool Utilization from Material Removal Rate Perspective2015In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 29, p. 109-113Article in journal (Refereed)
    Abstract [en]

    An end of life strategy algorithm has been used to study a CNC program to evaluate how the cutting inserts are used in terms of their full utilization. Utilized tool life (UTL) and remaining tool life (RTL) were used to evaluate if the insert has been used to its limits of expected tool life, or contributing to an accumulated tool waste. It is demonstrated that possible means to improvement exists to increase the material removal rate (MRR), thereby using the insert until its remaining tool life is as close to zero as possible. It was frequently found that inserts were used well below their maximum performance with respect to cutting velocity.

  • 135.
    Borgljung, Emil
    et al.
    University West, Department of Engineering Science.
    Hallquist, Pontus
    University West, Department of Engineering Science.
    Framtagande av systemdokumentation i Febdok och kontroll av skyddsinställningar för Nouryon AB i Stenungsund2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nouryon Ab is a leading company in the processing industry The company is dependant on a safe and robust supply of electricity to operate its processes continuously. The company has started to implement Febdok to assess the current state of the power system regardingfault currents, selectivity, voltage drop and disconnection times. The goal with this project is to create a system documentation in Febdok for one of the low voltage switchgears.

    All parts of the chosen low voltage switchgear have been modelled in Febdok. Calculations has, however, been limited to only include three radials. The chosen radials are a motor, a self-regulated heating cable(eltrace) and two power connections used for alternative power supply for two other low voltage switchgears. The thesis presents the given low voltage switchgear and explains all parts of the switchgear as well as showing how Febdok is used tomodel the switchgear. 

    Information regarding the switchgear’s protection units, cable lengths and load currents are obtained from the employer and are implemented into the software enabling electrical power system calculations. To validate the results from Febdok calculations have also been madeby hand.

    The method for short current calculations is described in the report and the result of the calculations are presented in tables where the calculated values are compared to the calculated values in Febdok. The result of the comparison shows that the calculations correspond with each other in most parts of the power system. However, in combination with transformers the results can differ. In addition to short circuit calculations also disconnection times and selectivity have been studied with help of Febdok’s built in functions which provides selectivity plans and current/time diagrams. Here it has been found that the disconnection time of the Miniature Curcuit Breaker (MCB) protecting the eltrace is too long. All the Matlabscipts that have been used for the calculations can be found in the end of the thesis.

    The project shows how a detailed system documentation can be created in Febdok and that the manual calculations corresponds well with the calculations made by the program. The thesis creates a good platform for future projects addressing model creation in Febdok and further documentation of more radials of the low voltage switchgear.

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  • 136.
    Borgljung, Karl
    University West, Department of Engineering Science.
    Optimizing automation design: Highlighting key factors with an innovative assessment matrix: Concluded with a case study to validate2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Automation is a broad topic with many difficulties. Without extensive knowledge of the subject, it’s easy to forget important aspects when a production line is to be automated. This degree project aims to assist companies with this process by constructing an assessment matrix that will from asking different questions generalize the intended process and give feedback on a suitable strategy for automating it. The assessment matrix is in this degree project tested with Ultramare AB, a Swedish producer of air filters, in one of their manual production lines. To be able to construct the assessment matrix and understand what questions to include and exclude the project started with an extensive literature study. The literature study aimed to distinguish important factors in automation as well as understand what difficulties might arise when going from manual production to automated.

    The assessment matrix was capable of predicting a suitable way to continue with their design phase and a crude simulation has been done for all automation parts to showcase the results obtained. While the assessment matrix is at an acceptable level of gaining results it was clear during the literature review that there is much potential to go further with a tool like this. This degree project has scraped the surface on all sub-subjects to create a basis to work with during this time limit. but if one is to delve deeper into the subject much more can be found and constructed to create a larger, more accurate assessment matrix.

  • 137.
    Bourreau, Louis
    University West, Department of Engineering Science.
    Simulation of a sawing line using Discrete Event Simulation: A Comparative Analysis of Different Scenarios2023Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A sawmill operation uses many techniques, such as debarking, sawing, drying, and planning, to convert unprocessed logs into timber products. To achieve maximum productivity and satisfy client needs, effective coordination, resource management, and quality control are essential.

    Sawmill operations may make use of simulation approaches including Discrete Event Simulation (DES), System Dynamics (SD), and Agent-Based Simulation (ABS). By simulating the flow of logs and timber, DES can improve workflows and resource efficiency. SD offers perceptions on feedback loops and causal interactions. ABS provides extensive analysis by modelling individual agents and their interactions.

    The investigation began with a thorough data analysis and modelling approach for the sawmill system. There were efforts made to collect qualitative and quantitative data, which were rigorously validated. The system's basic features and processes were then shown in a conceptual model. To test several elements of the system's performance, simulation scenarios were run on the ExtendSim platform using a certified digital model.

    The influence of buffer sizes on sawmill throughput and efficiency was studied, and it was discovered that changing buffer sizes enhanced production efficiency and reduced waiting times. Strategic buffer allocation resulted in greater efficacy and lower wait times.

    Another set of tests looked at process delays and how they affected sawmill productivity and throughput. Although effective workflow management reduced process durations, the boost in productivity that resulted was not statistically significant.

    After looking into input fluctuations (log quantity and quality), the study showed that the best input combinations for increasing sawmill productivity could be determined based on the products that were produced. Controlling input variance turned out to be crucial for raising system efficiency as a whole.

  • 138.
    Bradley, Jonatan
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Höglind, Fredrik
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Anti-Virus resursutnyttjande2016Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    How does Anti-Virus software affect the computer performance? Avast, Windows defender, Eset Nod32 and Symantec are a few of the big Anti-Virus companies that specialize in protecting your computer by removing virus, malware and trojans. Four Anti-Virus software and three scenarios was chosen to test cpu, memory, networks effect of the Anti-Virus software. Every scenario were tested three times ten minutes for every Anti-Virus software. Five minutes composed of a baseline and no test performed, after five minutes we conducted the test. Results differentiated between the different scenarios. Altogether, the Anti-Virus software differentiated minimal between each other. The data showed that the free Anti-Virus software was every bit as good as the paid Symantec version in utilizing the computer resources.

  • 139.
    Bragander, Vilma
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Berner, Madeleine
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Surfar den yngre generationen säkrare på internet?2021Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    The general opinion is usually that the younger generation is acting safer on the Internet, since this generation has grown up with technology in their lives. But is this really true? In this study we find out about this by publishing an online survey for the general public and gather answers from different age groups. The survey covers multiple topics that we considered to be important aspects of the individual safety on the Internet. The issues that are answered is this study is: Has a certain age group been exposed to more cyberattacks than others? Do some age groups have higher security considerations on the Internet than others? What does the general password management look like in the different age groups? We gathered and analysed the answers from all the respondents and came to the conclusion thar the theory we had in the beginning of this work did not match the results. The younger generation creates and builds stronger passwords and use services to make intrusion into user accounts more difficult. However, this is the only aspect that the younger respondents handle better. The result clearly showed that the older respondents usually had greater security concerns than the younger ones and generally acted safer on the Internet. 

  • 140.
    Brahm, Fredrik
    et al.
    University West, Department of Engineering Science.
    Kristiansson, Lennart
    University West, Department of Engineering Science.
    Wennerström, Joakim
    University West, Department of Engineering Science.
    Energimätning vid Högskolan Väst2011Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Svenskarna är med en elförbrukning av cirka 15000 kWh per person de fjärde största elför-brukarna i världen. Det beror främst på det kalla klimatet, men även stora industrier med hög elförbrukning bidrar till konsumtionen. Högskolan Väst förbrukar årligen 3 miljoner kWh. Med stigande elpriser och ett ökat fokus på miljöpåverkan önskar skolan att sänka sin förbrukning.

    Examensarbetet har utförts på uppdrag av kWh kontroll och NEA gruppen. Mätningar har utförts på matande ledning till skolans alla huskroppar samt dess ventilation. Syftet med examensarbetet var att lokalisera energiförbrukare inom Högskolan Väst och ge förslag för att minska förbrukningen med fokusering på minskad belysning nattetid och helger. För att mäta elförbrukningen användes elkvalitetsanalysatorer och enklare energimätare.

    kWh kontroll har som mål att sänka elförbrukningen med 6 % vilket motsvarar 180000 kWh per år. Under Earth Hour sänktes förbrukningen med 40 kW i huskropparna E-J och 10 kW i huskropparna B-D. Baserat på dessa resultat skulle det genom att släcka ner natte-tid, då skolan är larmad, innebära en årlig besparing på 115000 kWh.

    Energimätningar har även gjorts på datorer och resultatet visade att om strömmen till sko-lans datorer kan brytas under larmad tid skulle detta ge en besparing på cirka 8200 kWh om året.

    Rapporten visar att Högskolan Västs elförbrukning under nattetid går att reduceras enligt de olika förslag som beskrivs.

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  • 141.
    Brandt, Otto
    University West, Department of Engineering Science, Division of Production System.
    Virtual commissioning of the PTC production line2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 142.
    Bratt, Johan
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Selektivitet i mindre nätstationer2000Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Uddevalla Energi Elnät AB (UEE) is a distribution system operator which is a subsidiary of Uddevalla Energi AB. UEE has the right to build and operate distribution systems within its concession limit. Within the grid there are more than 500 secondary substations. The grid is about 170 km long from Ljungskile in the south to Uddevalla in the north and Öresjö in the east. 

    UEE has a governing document for the use of high-power fuses in relation to the rated power of the transformer. The document describes and clarifies the operations and maintenance department's requirements and wishes for electrical installations for both new and remodeling.

    The purpose of this report has been to produce a proposal for an update of the governing documents. A solution proposal has been developed regarding the errors identified by the UEE regarding non-selective triggering of total and sub-area fuses depending on the type of error in the underlying network. In addition, recommendations regarding the selection of the largest group fuse for outgoing groups in scenarios with and without overload protection of the transformer. The report provides UEE with basis for future projects for new and rebuilding of substations.

    The study has been designed as a system study where modeling has been done of three type secondary substations with transformer sizes 100 kVA, 200 kVA and 315 kVA respectively. Dimensioning currents have been calculated to produce suitable fuses. The conditions for the three models have been calculated manually and have been retrieved from the UEE's NIS program Digpro. This has contributed to the possibility of being able to compare manual calculations with calculations made in the NIS program.

    The results of each model station show that the use of sub-area fuses is the best alternative as short-circuit protection in all models. The result also gives a recommendation of size choice for fuses as overload protection for the transformer and the largest group fuse for outgoing lines

  • 143.
    Brattberg, Anton
    et al.
    University West, Department of Engineering Science.
    Paling, Sebastian
    University West, Department of Engineering Science.
    Develop test method for measuring bearing current in an electrical machine2022Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The automotive industry is heading for an electrified future and that brings new challenges for the validation processes. This thesis project was carried out at Volvo Cars in Gothenburgat their validation department for electrical propulsion. The goal of this thesis is to propose a test method for measuring bearing currents in a permanent magnet synchronous machine. Bearing currents are electrical discharges between the rotor shaft and stator frame going through the bearings. These discharges can damage the bearings and thus is a large contributor for premature failure in electrical motors. By reviewing and evaluating several methods,two final methods were chosen for future testing. The two chosen methods were insulated bearing current- and shaft voltage measurement. A physical validation of bearing insulation was attempted without success, even thou these methods are still recommended for future work.

  • 144.
    Bring, Hampus
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Emanuelsson, Olle
    University West, Department of Engineering Science, Division of Automation Systems.
    Vinkelfelet i mätkretsens påverkan på riktade jordfelsskydd2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor's thesis examines the angular error in the measurement circuit for directional earth-fault protection and how this error affects the fault disconnection. Angular errors in the measurement circuit can affect the directional earth-fault protection in such a way that the real fault current and the measured fault current do not match. This can lead to missed or unwarranted fault disconnections. Vattenfall has a requirement which states that the angular error must not exceed ±2 degrees for the measurement circuit. Since the angular error in many cases has a high impact on the earth-fault accuracy, an investigation concerning what Vattenfalls angle requirement really means. The main cause of the angular error usually occurs in the current transformers and therefore two commonly used current transformers in the grid with different classifications and their impact on the angular error in the measurement circuit are examined.

    Ground fault is the most common fault which occurs in a distribution network, its size depends largely on the amount of capacitive current which the grid contributes with as well as the size of the neutral grounding resistor. The capacitive contribution of the grid compensates centrally in the distribution station and sometimes locally on the line. The maximum permitted centrally compensated part of a line is limited to 30 A, this central part can go up to 60 A in case the line needs to be fed from a second distribution station. The angular error has a higher impact if the capacitive contribution is high and for low values of the neutral grounding resistor. In many cases more than one earth-fault protection are found on the same line, in these cases selectivity is always pursued. The angular error may have a negative effect on the selectivity.

    By calculations, simulations and tests a number of conclusions can be drawn. Vattenfalls

    angle requirement gives an unclear picture concerning the permitted impact on the earthfault

    protection. Moreover selecting the correct current transformer demonstrates that the

    angular requirement can probably be sharpened. To reduce the influence of the angular error

    the maximum permitted centrally compensated part be reduced and/or the value of the

    neutral grounding resistor can be increased. A selectivity of 1000

    Ω can not always be applied

    since certain cases require a selectivity of 2000

    Ω. By setting the zero sequence voltage as the

    trigger condition and the zero sequence current as the realese condition, according to this

    study it may be possible to achieve a more accurate earth-fault protection.

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  • 145.
    Brinkheden, Dan
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Andersson, Robin
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    A Performance Study of Hybrid Mobile Applications Compared to Native Applications2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study evaluates the performance difference between hybrid and native mobile applica-tions when accessing the low level API. The purpose of this study is to find out the differ-ence in performance between the different methods for developing applications due to an increasing market for platform independent applications.

    Several benchmarks were created to measure the performance on the following criteria, execution time, memory allocation and storage space. The benchmarks were developed with a similar behaviour to match the functionality.

    The Titanium benchmarks were around 8.5 times larger in storage space and used 26-28% larger heap when it came to memory than the equivalent Android benchmarks. Android generally has a lower execution time than Titanium, however there are cases such as the math library where Titanium has a lower execution time.

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  • 146.
    Britte, Johan
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Kratzer, Björn
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Ottersten, Christian
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Förutsättningar för mikroproduktion med vindkraft för Byggnad 73 på Innovatum2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In today's society environmental friendly electricity is sought after. This thesis will discuss the prerequisites to produce electricity from micro production wind turbines adjacent to Building 73 Trollhättan, situated in an urban environment.

    This thesis compiles information about wind turbine technology and the laws, rules and recommendations to be followed while constructing a wind turbine in urban environments. A market research of the Swedish micro wind turbine market has been concluded. From the market research results two suitable wind turbine proposals has been presented. During the process it was revealed that there are different definitions of micro production. There is also many different laws, rules and recommendations that you have to consider while constructing a wind turbine. It was established that it is important to examine the prerequisites of the environment in the area where you plan to place the wind turbine for example you have to consider obstacles and average annual wind speed.

    The prerequisites of the building were established and contact with Kent Andersson building-and equipment manager was made. We discovered that the electricity contract was too large for connecting of micro production and the construction of the building was too weak to support the weight of a wind turbine. Even though these aspects were disregarded we came to the conclusion that wind power in an urban environment is not appropriate for many different causes. But micro production in form of wind power is suitable in a rural environment where many of these causes do not exist.

    The group has disregarded these aspects when the two wind turbine suggestions were formed. Of these two suggestions one is mounted on the roof and the other on the ground besides the building. The two wind turbines that came to be chosen were Winden 30 and Villaverket Maglev 10 kW. Winden 30 is a wind turbine with an effect of 30 kW that should be placed on the ground beside the building and is made in Sweden by Winden Sweden AB. Villaverket Maglev 10 kW which is made by Nordh Energy and is supposed to be placed on the roof of the building.

    In this thesis the economic aspects of wind turbine construction has been disregarded.

  • 147.
    Broberg, Patrik
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Sjödahl, Mikael
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Improved Corner Detection by Ultrasonic Testing using Phase Analysis2013In: Ultrasonics, ISSN 0041-624X, E-ISSN 1874-9968, Vol. 53, no 2, p. 630-634Article in journal (Refereed)
    Abstract [en]

    In ultrasonic testing, corners are used for sensitivity calibration in the form of notches, for measuring the sound velocity in the material, and as known reference points during testing. A 90° corner will always reflect incoming waves in the opposite direction due to a double reflection and therefore give a strong echo. This article presents a method for separating the echo from a corner from other echoes and more accurately find the position of the corner. The method is based on analysing the phase of the reflected signal. The proposed method was tested on a steel calibration block and the width of the indication was reduced by up to 50% compared to the amplitude signal. This results in a more accurate positioning of the corner. Using the phase instead of the amplitude will also improve the reliability, since reflections other than from corners will disappear.

  • 148.
    Broberg, Patrik
    et al.
    University West, Department of Engineering Science, Division of Process and Product Development.
    Sjödahl, Mikael
    University West, Department of Engineering Science, Division of Process and Product Development.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Process and Product Development.
    Improved Image Quality in Phased Array Ultrasound by Deconvolution2012In: Proceedings18th World Conference on Non-Destructive Testing: 16 - 20 April 2012, Durban, South Africa, South African Institute for Non-Destructive Testing (SAINT) , 2012, p. 1-5Conference paper (Refereed)
    Abstract [en]

    High contrast and resolution in phased array ultrasonic images are of importance for accurate evaluation. The spread of the ultrasonic beam is one cause of the images being unsharp. One technique for reducing the influence of the beam spread, and thereby improving the image quality, is by deconvolving the data with the point spread function of the ultrasonic beam. By assuming that the material is homogeneous, the point spread function of the beam can be simulated using diffraction theory. Results from a deconvolution performed on data acquired from a side drilled hole in a steel calibration block are presented. It is shown that a significant improvement in sharpness and contrast can be achieved.

  • 149.
    Bräck Nordman, Natalie
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Utredning av Uddevalla Energis elnätskapacitet med avseende på Uddevalla kommuns framtida utbyggnadsplaner i centrum2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This preliminary study has been carried out at the department for operation and maintenance at Uddevalla Energi. The purpose has been to investigate the capacity of the powerlines with regards to Uddevalla Council's future development plans in the port and to identify strong and weak points.

    During a future 25-year period, Uddevalla Council plans to gradually expand the city center towards the harbor area, which today consists of industries and business facilities. The council estimates that the new district will be able to provide 3000 new homes and various types of businesses. The time frame for the exploitation plans are 5-15 years for the southern side of Bäveån and 20-25 years for the northern side. In order to investigate whether there is available power for the additional district, a load forecast is made of the future power requirement. A survey and analysis is made of the lines in central Uddevalla and the transformers of the substations M1, M2 and M5. This is made in order to be able to investigate whether any reinforcement is needed. Reference the values used in the calculations are based on measured values from the peak of load on February 28, 2018.

    The expected power requirement for the planned residential areas is estimated at 4.9 MVA for the south side and 5.1 MVA for the north side.  The cable network in the port has a total capacity of 7 MVA and will be almost saturated after the southern area’s construction is completed. With regard to redundancy, all substations are able to supply an additional residential area on the south side alone, while only M1 has the capacity for the entire forecasted load. The transformers in M2 and M5 will be overloaded only during the development of the residential area on the north side. To the future expansion of the city center, suggestions for placement of three new lines from M1 are made. In connection with the installation, most of M1-L206 can be replaced, which consists of undersized oil cables. The cost for this amounts to 10,3 million (SEK).

    Another future option that would have to be investigated more closely is how the possibilities are to place a new substation in central or southern Uddevalla. The existing ones are located in the northern, western and eastern parts of the city.

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  • 150.
    Buvarp, Daniel
    University West, Department of Engineering Science.
    Design and Evaluation of Heavy Electric Vehicle DC Charging Overcurrent Protection2022Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The vehicle industry must reduce emissions to lessen their environmental impact. Using electric motors for propulsion and batteries for energy storage decreases the pollution and greenhouse gases emitted by heavy commercial vehicles such as trucks and buses. As they often travel long distances, a large energy storage is needed, and it needs to be possible to recharge it quickly. The fast recharging requires high power chargers with high voltage and high current, and that in turn necessitates a suitable overcurrent protection system to avoid damageif a fault would occur.

    Possible technologies for this overcurrent protection system are investigated in this thesis, and the different solutions are evaluated based on important metrics. A solid state breaker is found to be a promising technology that limits the current quickly and reliably.

    The evaluation including computer simulations shows that the technology is feasible, but some aspects of the circuit design need to be executed carefully like the inductance, the sampling frequency of the current measurement, and the design of the snubber circuit.

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