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  • 51.
    Andersson, Frida
    University West, Department of Engineering Science.
    Nätanalys av området Överby i Trollhättan Energis elnät2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Elektrifieringen som råder inom olika branscher ställer idag höga krav på Sveriges elnät. Det väntas en stor effektökning som dagens elnät inte är rustat för och detta gör att elnätet på lokalnätsnivå behöver utvecklas och förstärkas. Syftet med arbetet är att undersöka huruvida det befintliga elnätet i området Överby iTrollhättan har kapacitet nog för det framtida effektbehovet som förväntas tillkomma i området och därmed säkra elleveransen till närliggande anläggningar och kunder. Arbetet innefattar nätanalys av utgående ledningar från två mottagningsstationer, M1 och M2, som är lokaliserade i närområdet kring Överby. Med hjälp av olika programvaror så som Mickel och MapGuide har detta arbete kunnat utföras enligt tidsplan. Effektberäkningar har gjorts utifrån data som insamlades via dessa programvaror och har använts för att analysera det befintliga elnätet. För att sedan kunna utföra en analys på hur framtiden kan komma att se ut har antaganden angående framtida effektökning gjorts. Effektökningen kommer till största del bero på tillbyggnad av bostäder och utökning av laddinfrastruktur för elfordon. På grund av att långsiktiga utvecklingsplaner för området saknas är framtida effektökning osäker. Två fall har därför tagits fram där olika effektökningar studerats.För det första fallet har en effektökning om 20 MW undersökts. Detta resulterade i att elnätet behöver utökas med nio nya kablar som beräknas vara belastade ca 50 %. När så pass mycket effekt skall tillkomma behöver ytterligare nätstationer placeras ut i området. Här motsvarar effektökningen 15 fullastade nätstationer med transformatorstorlek 1250 kVA. Kostnaderna för detta alternativ beräknas till ca 26 miljoner kronor. Det andra fallet innefattar en effektökning på 12 MW vilket resulterar i en förstärkning av elnätet med sex nya kablar från mottagningsstationerna. Här motsvarar effektökningen nio fullastade nätstationer med samma transformatorstorlek som tidigare nämnts. Kostnaderna för detta alternativ beräknas till ca 18 miljoner kronor.  

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  • 52.
    Andersson, H. Robert H.
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    de Blanche, Andreas
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Lundqvist, Thomas
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Flipping the Data Center Network: Increasing East-West Capacity Using Existing Hardware2017In: 2017 IEEE 42nd Conference on Local Computer Networks (LCN), 9-12 Oct. 2017, IEEE, 2017, p. 211-214, article id 8109355Conference paper (Refereed)
    Abstract [en]

    In today's datacenters, there is an increasing demand for more network traffic capacity. The majority of the increase in traffic is internal to the datacenter, i.e., it flows between different servers within the datacenter. This category of traffic is often referred to as east-west traffic and traditional hierarchical architectures are not well equipped to handle this type of traffic. Instead, they are better suited for the north-southbound traffic between hosts and the Internet. One suggested solution for this capacity problem is to adopt a folded CLOS topology, also known as spine-leaf, which often relies on software defined network (SDN) controllers to manage traffic. This paper shows that it is possible to implement a spine-leaf network using commodity-ofthe-shelf switches and thus improve the east-west traffic capacity. This can be obtained using low complexity configuration and edgerouting for load balancing, eliminating the need for a centralized SDN controller.

  • 53.
    Andersson, Helen
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Analys av ett distributionsnät i en bangård2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    An analysis of an electrical distribution system located in a railway yard have been requested by Atkins Global AB. The system includes electrical distribution to signal equipment, heating equipment for the switches and lightning for the platforms.

    The initial part of the analysis consisted of a literature study regarding requirements for this type of system and the gathering of data regarding the cables and the fuses in it. The cabling are either of the type FXQJ or AXQJ. The system is normally powered from a three-winding transformer via two centrals, the first central A1 supplies the signal equipment electricity, through the subcabinet F3, and the lightning both powered by a main voltage 400V and central B1 powers the equipment for heating the switches with the main voltage 230V. The distribution from B1 consists of two parallel cables feeding a subcabinet FS4/36.There also exists an auxiliary power supply from a smaller transformer T3, used if the main power supply should disappear.

    The remaining investigation was conducted in the calculation program MyEcodial by Schneider Electric. The investigation focused on personal safety and short current calculations. The result was a series of suggested changes regarding the fuses and cables in the system.

    The results of the investigation regarding the powering of the signal equipment was such that a recommendation to change the cable going from F3 to one of the signal cabinets to an AXQJ 3x95/29 cable and to conduct a current measurement regarding if the present 100A fuse can remain or if it should be switched to an 80A fuse. From F3 to both the main power supply and the auxiliary power supply new fuses with 200A must be put in to ensure that the cables are protected. For the powering of the lightning it was the selectivity between the fuses that was the problem since they both had the size 63A, the investigation proved that it was the lower fuse that should be replaced with a fuse with highest 50A and lowest 32A. Regarding the power supply for the heating of the switches it is once again necessary to do a current measurement to determ if it is possible to switch the present 400A fuse to a smaller one on 315A. If not then two more cables of the same size as the present ones must be installed parallel to the present ones to ensure safety for people.

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  • 54.
    Andersson, John
    University West, Department of Engineering Science.
    Analys av påverkan från ökad mikroproduktion och installation av laddare för elfordon i lågspänningsnät2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In Sweden, the number of rechargeable cars increases for every year. It is common to charge at home, for example because there is no need to wait for the vehicle to be fully charged.Charging at home takes place with low effects for longer time periods. The installation of micro production with photovoltaic systems is also increasing. Lidköping Elnät sees that the number of installations of chargers for electric vehicles and installation of micro production are increasing in the concession area and are expected to increase even more in the upcoming years. This study investigates the voltage variations that occur in an older and a newly constructed area with villas within the Lidköping urban area under normal load, as well as two future scenarios for micro production and chargers for electric vehicles. The work addresses which actions must be implemented in each area and what the actions cost.The voltage variations have been generated through calculations of the mentioned scenarios in the existing low voltage grid connected to the substation and the associated transformer in each area. Calculations on the low voltage grid at normal loads are based on consumption data take from Lidköping Elnäts’ system for debit measurement. In case of high production, a value is set for the photovoltaic systems that Lidköping Elnät considers as a normal size when a pre-registration of micro production is received. When charging electric vehicles, high consumption in the grid is assumed in the calculations. The voltage variations in the grid are added to the voltage variations occurring over the transformer to calculate the total voltage variations for the grid.Calculations of the total voltage variations in the grid for each scenario demonstrates that none of the points in the grid falls outside the limits allowed by the Swedish Energy Markets Inspectorate or European standard for voltage variations. At high production or high consumption the voltage increases or decreases for the weakest points fall outside the recommended limits for calculations. The high consumption scenario had the highest percentage differences form the reference voltage of 0,4 kV in both areas, which led to this scenario being used as the starting point for the development of actions.The actions developed reduce the voltage drops in both areas to be within the recommended limits of Swedenenergy, but also Lidköping Elnäts’ stricter limit for new connections. Lidköping Elnät is only obligated to implement an action if the voltage variations fall outside the limits set by the Swedish Energy Markets Inspectorate and the European standard or if complaints are received and poor power quality can be demonstrated.  

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  • 55.
    Andersson, Johnny
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Karlsson, Robin
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Uppstartsguide för Febdok2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete har utförts på ÅF Industry i Trollhättan. Syftet med examensarbetet är att arbeta fram rutiner och ett standardiserat arbetssätt i Febdok. Detta för att underlätta och spara tid vid användning av Febdok. Inledningsvis påbörjades framtagning av relevant teori kring den definierade problembeskrivningen tillsammans med handläggaren på ÅF. Parallellt genomfördes övningsexempel i Febdok för att gruppen skulle få en insyn i hur funktionerna fungerar. Rapportens teoridel behandlar de mest problematiska- och tidskrävande funktionerna i Febdok så som UPS:er, kortslutningsströmmar och selektivitet. Det för att ge en förståelse om bakgrunden till funktionerna. Ett beräkningsexempel på ett fiktivt nät gjordes för att kunna verifiera en överslagsräkning som används på ÅF för att beräkna ett ungefärligt värde på minsta felström. Denna minsta felström erhålls vid enfasig jordslutning och definierar utlösningsvilkoret. Maximal felström delat på tre har ansetts ge ett någorlunda korrekt värde på minsta felström. Beräkningar på maximal- och minimal felström vid olika kablage jämfördes och visade att överslagsräkningen inte är att rekommendera på grund av att minsta felström ibland bli lägre. Istället bör en faktor av minst fyra användas vid överslagsräkningen för minsta felström. I avsnitt 3 i rapporten beskrivs initiala inställningar och funktioner i Febdok med föregående teori som bakgrund. Implementering av UPS:er i Febdok visade sig kräva mer datainmatning än vad som normalt går att få tag på från tillverkare. Genomsläppt energi är data som visade sig svår att få tag ifrån olika tillverkare. Vid närmare tester av programmet och dess funktioner visade det sig att genomsläppt energi inte behövs definieras i UPS-funktionen för att arbeta med selektivitet och kortslutningsströmmar längre ut i anläggningen.

    Resultatet av observationerna i Febdok och teorin visade att tumregeln som används på ÅF inte är att föredra och säkringar i en anläggning försedd med UPS bör dimensioneras efter batteridrift. Informationen och kunskaperna som samlades under arbetets gång samanställdes i en uppstartsguide för Febdok. 

  • 56.
    Andersson, Jonathan
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Birgersson, Alexander
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    IPv4 vs. IPv6: Vilket ska du surfa med?2020Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report addresses latency and response-time comparisons between the IPv4 and IPv6 protocols. These protocols are necessary to deliver data to the right recipient on the Internet as it is the TCP/IP model that is used. IPv6 is a newer version of IPv4 and was created in the late 1990's because the IPv4 addresses will not be enough for all devices that will come to need it. In association with the transition to IPv6, an opportunity was taken to optimize the protocol with fewer fields in the header and thus try to increase the latency and response times over IPv4.

    The report shows similarities and differences in latency and response times between IPv4 and IPv6 when browsing popular websites, a relevant use case that occurs daily. Measurements are made by downloading the web pages with the http protocol with both the IPv4 and the IPv6 protocols and then analyzing the different response times between them. This is done for three different internet providers: Telia, Bahnhof and Sunet. Telia also uses a different IPv6 solution than the other two, which will be another factor in the analysis.

    The results of the measurements show that IPv4 performs somewhat faster for all internet providers but does not make a directly noticeable difference for an end user. The traffic takes largely the same route regardless of which of the two protocols is used. The time for DNS lookups takes considerably longer for Sunet as an Internet provider than for the other two. The difference in route choice depending on which protocol is used is most noticeable for Bahnhof. 6RD performs a better average time than Sunets native IPv6.

  • 57.
    Andersson, Kristian
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Jason, Evelina
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Beskrivning och vidareutveckling av en modell för beräkning av övertoners fördelning i distributionsnät2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this report is to describe and develop a model used to determine demand permissions regarding power quality on behalf of Vattenfall Distribution. The purpose of the model is to calculate the level of current harmonics allowed for different types of energy subscriptions by studying how harmonics spread in a power grid and how subscribers affect each other. This model needs to be described seeing that the documentation of the original model was lacking. The model also needs to be further developed to increase the flexibility and its ease of use.

    Harmonics are a phenomenon that occurs on the power grid and are generated by non-linear loads like EV-chargers and photovoltaic systems. If the harmonic distortion level is too high, grid connected electronics can experience issues or stop working.

    There are a number of standards, reports and regulations regarding emission rights considering harmonics. This report summarizes three of these as a background to how emissions are regulated today (2018). Two of these papers focus on voltage harmonics levels which is also the case for Vattenfall Distributions governing documents. Vattenfall Distribution needs to develop a new method to determine these current harmonics emission levels, and the model is a part of that process.

    A thorough analysis and mapping of the model were made to produce the documentation for the model. The model was then further developed to allow for more flexibility and could be simplified compared to the original model.

    The original model is considered to fulfil its purpose and therefore no structural changes have been made. The changes that have been made have been implemented to make the model as flexible and user friendly as possible. To help the user to understand the model, a flowchart was made to describe the structure and internal workings of the model.

    The authors believe that a thorough and detailed documentation of the model has been produced and that the model fulfills the purpose of producing representative values to determine demand permissions regarding power quality. The model has been restructured and is now perspicuous and easy to use. However the result from the model is highly dependent of the input data and it's important that it is of good quality.

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  • 58.
    Andersson, Leon
    University West, Department of Engineering Science.
    En undersökning om Linux förmåga att hantera processer som överkonsumerar minnet2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Minneshanteringen i operativsystemet Linux för processer som överkonsumerar minnet kan variera beroende på vilken Linux baserad distribution som används. Detta innebär att systembelastningen av ett minnestungt program kan ha olika effekt på olika system. I denna rapport presenteras två typer av systemlösningar med avsikten att hantera scenarion då minneskonsumtionen är ohållbar för att undersöka och jämföra respektive systems agerande och betydelsen detta har för det fullständiga systemet. En lösning agerar i kernel space och en som agerar i user space hos systemet. Av dessa agerar user space lösningen som ett komplement till kernel space lösningen. Inte alla Linux distributioner använder denna konfiguration. Genom att skapa ett program som medvetet överkonsumerar systemets minne testas båda lösningar. Programmet agerar som ett stresstest där resurskonsumtion berörande programmet samt totala systemet undersöks. Resultat indikerar att user space lösningen komplimenterar kernel space lösningen på ett noterbart sätt genom att agera proaktivt och förebyggande genom att förhindra överkonsumtion av systemets minne. Medans kernel space lösningen enbart agerar som en nödlösning när systemets totala minnesresurser har förbrukats.

  • 59.
    Andersson, Markus
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Jonsson, Fredrik
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Säkerhetsanalys av interna IT-säkerheten på ett mellanstort företag2018Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This thesis is about a security analysis of a company's use of IT and their internal network security. The company is a midsized with about 100 employees and half of them use IT in their daily work. The company is active within industrial manufacturing and is located in western Swe-den. They want to develop in IT and are curious about how secure their network is today.

    A review of the layer 2 network security and computers used in the daily work was performed and evaluated. Anonymous interview of employees were made to find out how IT is used at work. A risk analysis was filled in by the responsible employees at the company to get an overview of how they think about risks and vulnerabilities in the use of IT. All this was done to bring recommendations to the company about how they can improve their security compared to what it is today.

    The results from the analysis of the network indicates weaknesses in the layer 2 security and that no security features are currently used to stop attacks from the inside of the net-work. The company has no high demands on the network or the security on the in-side but has given priority to flexibility and physical security.

  • 60.
    Andersson, Martin
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Hägerström, Martin
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Sammanställning av utbildningsmaterial om reservkraft med inriktning dieselaggregat2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today's society is composed of a constant energy dependency to get all functions of the modern society to function, a power failure can be devastating. Even though Sweden has a strong power grid, the requirement to always have access to electricity has opened up a market for back-up power. The aim of this work was to create material that could be used in educational purpose and for the reader to get a basic understanding of back-up power with focus on diesel generated power. The course material consists of recommendation of content in the form of page references from sources that fit well in the compilation ofeducation material in the form of a compendium. The compendium is supplemented with a layout of a PowerPoint presentation that can be used for educational purposes. By studying the relevant sources, we have deepened in our topic diesel generated power and have picked out page references, in accordance with the agreement regarding the school copy law, which we consider to be a good fit for the creation of a compendium. We have also created a foundation to a PowerPoint that can facilitate the creation of lecture material. This report explains the structure of a diesel power generator and what is important to consider when sizing a power system. The report also discusses recommended maintenance as well as the requirements placed on a diesel power generator.

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  • 61.
    Andersson Novela, Adam Xavier
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Westerlind Novela, Elsa Maria
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Enterprise servers' operating system performance during DoS and Slow DoS attacks2020Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Three different servers running three different server operating systems were subjected to the denial-of-service (DoS) attacks; UDP flood and Slow HTTP. Computers running Kali Linux were used as the attackers and the tools hping3 and Slowloris were used to perform the attacks. The first round of attacks was performed by one computer and the second round was performed by four computers simultaneously, this was to simulate DoS attacks and distributed denial-of-service (DDoS) attacks respectively. Results were recorded both before and during the attacks, to then be compared. The three Operating systems in question were Windows Server 2019, Ubuntu Server 19.10 and CentOS 8 Server, they all had the web server software Apache installed. The servers' average CPU usage and average memory usage were measured, these results were then compared and if any increase had occurred during the attack it would be deduced that the attack was impacting the server negatively, a higher increase meant a higher impact. During the Slow HTTP attacks the web servers were checked for availability, if it was not available then the attack was successful.

    During testing it was found that the Windows server had the worst performance during both attacks, showing the highest increase in hardware usage and the lowest uptime of the web page when being attacked.

    The Ubuntu server performed the best when looking at the CPU and memory usage, with little to no change from its baseline results and a higher uptime of its webpage than the Windows server.

    CentOS recorded less of a change in hardware performance when being attacked than the Windows server but more so than the Ubuntu server, it was, however, the server with the most uptime of the webpage when being attacked.

  • 62.
    Andersson, Oliver
    et al.
    University West, Department of Engineering Science.
    Stenvold, Isabelle
    University West, Department of Engineering Science.
    Förprojektering av ett lokalnät i ett landsbygdsområde2022Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is about the preparatory design of the local network in a rural area on behalf of Vattenfall Distribution in Sweden. The project includes the replacement of 16 substations, 33 km of high voltage (10 kV) cables, 16 km of low voltage (0,4 kV) cables and the demolition of overhead lines for both low and high voltage.

    The work involves two lines from a distribution station. One of the lines is new with an area of 240 mm2, it aims to take over the load in a newly built area with too high voltage drops that are currently fed from another distribution station. The newly built area has a voltage drop of 9% at present, with the new line the voltage drop will be 3.4%. The purpose of the second line with the area 150 mm2 is to replace the existing overhead line network with ground cables and connect network stations on the road. Because of difficult conditions the high voltage cables on part of the route are located in a lake. The network stations to which it is connected are updated because they are congested or do not have a divert option. 

    The low voltages overhead lines that are connected to the affected substations are replaced with ground cables. The quality of the distributed electricity is analyzed at the connected low voltage customer by checking pre impedance, selectivity and voltage drops. 

    Compensation of capacitive earth fault currents occurs on both cables, compensation is done with Petersén coils that are placed in substations.The cost calculation is based on a P1 level from EBR cost catalog and amounts to 36.8million SEK.

    The cost was higher than expected due to several aggravating factor such as a higher number of substations and longer overhead lines than expected, and difficult ground conditions for the cables. 

  • 63.
    Andersson, Per
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Automated Surface Inspection of Cross Laminated Timber2020Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The use of wood, such as Cross Laminated Timber (CLT), has increased over the last years in the construction of buildings. CLT is primarily considered a structural component inside walls, floors, and ceilings. But, when the design specifies an exposed surface of the CLT, where the wood surface will be visible in the finished building, there are requirements on the visual appearance of the CLT. To fulfil the requirements visual inspections of wood defects of the surface are conducted, before the CLT-panel is shipped to the construction site. Human inspectors are not consistent evaluators of products, and their accuracy depends on factors such as expertise, motivation, and fatigue. This study proposes a solution to automate the inspection, where captured images are analysed by an object detection model, based on deep learning. The model Faster R-CNN has proven to be successful in medical image processing and for object detection. A challenge with deep learning models, such as Faster R-CNN, is the number of test images needed to train the model. Also, there are a limited number of suitable test images of wood defects available. By using a pre-trained Faster R-CNN model and adapt the model's skill to detect wood defects, instead of the model's intended objects, the model can be trained with a relatively small number of test images. This study relies on images of planks, similar to the ones used in CLT, and the number of test images in the study is very limited. To improve the results, the model needs to be trained with more test images of CLT-panels. Nevertheless, the model can locate the defects in the CLT-panel and identify the type of defect to a high degree. The results indicate that the proposed model can be used to automate the inspection of wood defects on the CLT surface.

  • 64.
    Andersson, Rebecka
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Framtagning av styrdokument för elanläggningsinnehavare2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A control plan is a document that makes the maintenance work more efficient. These documents can for instance be used on a power plant to maintain routines and inspections on the electrical equipment. It is the plant owner's responsibility to ensure that the plant and its associated equipment is checked continuously to ensure the safety of the plant. The frequency of the inspections and what needs to be checked is not mentioned in any laws or regulations. It is thereby up to the owner to decide the ranges and the need of which inspections that are implemented on the plant. This study has been made to simplify the decisions that the owner must take when developing the routine and inspection plans.

    The developed control plan is taken from literary studies and two interviews from two separate companies. Through a comparative study data has been produced that describes what should be performed during a visual inspection and functional controls on a power plant. The study is limited to equipment that is generally occurring in a restricted access area. The produced result is two control documents – one for patrols and one for functional controls. The documents show what type of inspection that should be performed during a control, while the report describes how often these routines should be implemented. The time intervals are produced from a comparison of four companies' routines. Two of the companies has been interviewed while intern documents at two other companies have been reviewed.

    The study has given insight into the inspections that are implemented in a restricted access area and the responsibility that power plant owners have on the plant. The sources are considered relevant to the study and the interviews have been made with persons that possess knowledge in the field of study.

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  • 65.
    Andersson, Robin
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Larsson, Jonas
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Jämförelse av riktade reläskyddsfunktioner i impedansjordade nät2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis describes how different values on a neutral grounding resistor and an uncompensated power distribution network affect the zero sequence current and the zero sequence voltage. If the neutral grounding reactor in the power distribution network is too overcompensated or undercompensated, the directional earth-fault relay may not work. The purpose of this study is to present the advantages and disadvantages of two different earth-fault functions. The two earth-fault functions that will be compared are an admittance-based earth-fault protection and a directional earth-fault protection with angle calculation between the zero sequence current and the zero sequence voltage.

    The capacitive earth-fault currents have increased in the distribution stations because the overhead lines are replaced with underground cables. The capacitive current must be compensated since the capacitance can cause an overcompensated or an undercompensated network. An uncompensated distribution network may cause the zero sequence current and voltage becoming too low so that the earth-fault protections do not detect an earth-fault.

    After the comparison of the two earth-fault functions it can be concluded that there is a minor difference between the both functions. There are some deviations in the test results conducted in a laboratory environment. It is not possible to state which one of the functions that is the most suitable to use in real power distribution networks, since no such tests have been conducted in this study.

    The authors of this thesis have presented some advantages and disadvantages of the two earth-fault functions

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  • 66.
    Andersson, Sara
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Mänsklig faktor: hur kan man få den svagaste länken inom IT-säkerhet starkare?2018Independent thesis Basic level (degree of Bachelor), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    In today´s IT environments, the role of the users becomes more important. In 2016 there were 200,000 crimes in Sweden that could be linked to social engineering attacks. These attacks are targeting the users and it is therefore important that users are aware of what they look like. This report is conducted in cooperation with a municipality in Västergötland, Sweden, and investigate four different methods to use when sharing IT information to their users. The methods differ not only in implementation but also in difficulty in the choice of words and expressions. The first method is a document of information taken from the municipality´s intranet. The second is also a document but is rewritten to simplify for the users. The third method is a video presentation and the fourth was made as a lecture with the possibility of interaction between the lecturer and the users. To evaluate these four methods two surveys were conducted. The first survey was performed before the users received IT information to create a baseline. After one and a half month the second survey was made. The surveys are compared to see how much the users remember and which method was most effective. The results indicate that the information on the municipality´s intranet is difficult to understand for the users. The other three methods provide a greater positive change in the user’s questionnaire response, indicating that users need a different form and structure when information is to be provided for them.

  • 67.
    Andersson, Tommy
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Lindell, Erik
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Kartläggning av begränsande faktorer vid fellokalisering med pulsekometod på mellanspänningskablar2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As the medium voltage network cables in Sweden is buried down in the earth, the demand of fault localization expertise increases. To keep downtimes in the network short, the importance of effective fault localization is necessary. This work is aimed to map and visualize limiting factors within fault localization with focus on the TDR -

    Time Domain Reflectometry. This work is a collaboration with Vattenfall Eldistribution AB.

    Problems with fault localization on medium voltage cables with the TDR have been detected. A multiple factors are contributing to this problem. The results of this study show that the cable construction is a significant part in which extent the TDR can be used. The report are also accounting for basic information about construction and types.

    The mapping also illustrates water treeing and how it affects cables in a negative way. Visualization of what causes water treeing and several actions such as triple extrusion, jacket testing and insulation testing is included in the essay. Further information about fault types, cable types, cable generations, instrument types and method types is given. All of them are affecting factors within the area of fault localization.

    Documentation is highly important for a successful fault localization procedure, which is clarified in the report. Besides documentation the cable condition and the influence on it affecting the result of fault localization is stated.

    A number of measuring methods and instruments are available to use when fault localization and testing are occurring. Every instrument has their own advantages and disadvantages. They also have their own respective area of usage. The basic principle of TDR is studied and explained accordingly. The other measuring methods, which are used in fault localization and testing, are shown more generally

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  • 68.
    Andlovic, Mihael
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    How real-world IP-distribution affects load balancing2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This essay looks at how IP addresses on the last octet are distributed and how they are balanced by different load balancer algorithms. We collected the data from a data center in Sweden to get real data. The IP addresses we collected were used with a load balancer using IP source algorithms. We used 4 different algorithms in different scenarios: the entire IP address, the first 3 octets, and the last octet with and without hash between two to five links/servers. The results were that the efficiency of the algorithm depends on the setup that is being used. Each of these algorithms did not have an even distribution, when comparing between two to five links/servers. The best overall distribution that did not have any weaknesses compared to the other algorithms was Nginx that uses the Bob Jenkins hash algorithm.

  • 69.
    Andreasson, Johan
    et al.
    University West, Department of Engineering Science.
    Fåll, Fabian
    University West, Department of Engineering Science.
    Krav på kundägd anslutningspunkt med produktionsanläggning2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Vattenfall Eldistribution AB is one of Sweden's largest grid owners and aims to make Sweden fossil-free within one generation. In order to cover Sweden's electrical energy needs in a fossil-free way, more renewable production plants are required. One of the production plants that is growing the most right now is solar cell plants. Swedish standards have rules for how production plants must be designed. Among other things, there are requirements on how the manual disconnection of the solar cells should work and that there must be a circuit breaker that can disconnect the entire production plant, also called a production circuit breaker. Due to different interpretations, this circuit breaker has been allowed to be placed in different ways, but now Vattenfall Eldistribution AB wants to use this work to develop a standardized way to install the production circuit breaker. Therefore, the main goal of the work has been to produce guidelines for how customers of Vattenfall Eldistribution AB should place the production circuit breaker in the plant.

    The work presents a comprehensive description of what a solar cell installation might look like and how the amount of these facilities have changed in Sweden. As the statistics show that the number of production facilities increases every year, it is important that there are clearer guidelines from grid owners. In addition, how Vattenfall Eldistribution AB handles a request to install solar panels has been investigated. Through calculations of the electricity network, it is determined how the connection of the production plant will be carried out.

    In order to achieve a result, it was necessary to gather information from several sources. Vattenfall Eldistribution AB shared what was important to them and how they would like the installations to be designed. As a supplement to Vattenfall Eldistribution AB's opinion, relevant standards and regulations were examined. In order to further justify the placement to customers, consideration was also given to the fire department's requests for solar cell installations. Based on the information from all sources, guidelines were created. These guidelines present different locations of the production circuit breaker. For each location the advantages and disadvantages are described.

    The conclusions of the work are that the production circuit breaker needs to be placed outdoors, either on the facade of the building or alternatively in the meter cabinet if it is outdoors. In addition to the location of the production circuit breaker, the inverter for the plant also needs to meet the requirements set by regulations, which is done by choosing an inverter that is on the list of "Rikta Rätt" from Swedenergy.

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  • 70.
    Andréasson, Kim
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Hagberg, Daniel
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning av iBeaconannonsering via smartphoneapplikation: Objective c och ASP.NET2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This degree project is performed together with the company Sigma in relation with the education Datateknisk Systemutveckling at Högskolan Väst in Trollhättan. The purpose of this project is to examine the new technology iBeacon and study if it is to prefer over simi-lar technologies when developing a system to use for advertisement. To accomplish this, a smartphone application is developed aswell as an administration interface, to be able to perform a user test of the product with a random selection of people.

    The goal with the project is to develop a working product that can be tested and used for the examination of the hypothesis. This report explains how the project is performed and in the end, the result that the user test shows is discussed.

  • 71.
    Antoine, Galluet
    University West, Department of Engineering Science, Division of Automation Systems.
    Kinect to control robot: New ways to interact with robots2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main goal of the thesis is to create a way to interact with a ABB robot by using a Kinect.The focus will be put on making the robot mimicking the user's arm movement. But otherway like voice control will be investigated.Two main part of the work are developed in this report. The first one is the software aroundthe Kinect to get the body data. The software developed provides the user a visual feedbackon what the Kinect see and allows him to choose what mode he wants to use. Two mainmode are implemented. A mimicking one which makes the robot mimicking the chosen armand a moving object mode which tell the robot to go to the user's position and set the toolas the user hand state.When all the data are gathered, they are sent to the robot using an IP socket and predefinedmessage to give him the desired order.

  • 72.
    Antonsen, Cristoffer
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Asplund, Oscar
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Guide för projektering inom högspänning2020Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is written with the purpose of forming a guide in the area of high voltage project planning, requested by Vattenfall Eldistribution AB. Another purpose with the guide is too introduce new employees to project planning. The material will be available at the company's shared servers. The thesis also contains profound theory about phase to ground capacitance and the fault current to earth through the previous mentioned capacitance.

    Literature studies and interviews was used to complete the creation of this guide. The guide was tested using fictitious powerlines in the calculation program Netbas for the purpose to ensure that the guide was user-friendly and worked as intended. The software program used for calculations is Netbas which is a master data system where the power grid companies store their net image and future buildouts. The interviews were used to give a picture of how the work structure of the department is today and what challenges exist within project planning.

    The work is done for the grid connection department and the roles that exist is connection- engineers and – technicians. The most commonly tasks at the department are customer initiated new connections, reconnections and extension of existing costumer subscription.

    The developed guide consists of ten steps which has its own chapter with instructions to perform a high voltage project planning. To give the user an overview of the guide and save time, a flow chart was made where the necessary steps are shown to make the work smoother. Some of the steps are more theory based to give the user a deeper understanding about the subject and some of the steps consist of instructions for the user to follow. The design of the guide was made in PowerPoint and zoom functions were used to enable a e-learning feeling.

    Another conclusion from the work is that is deals mostly with normal cases and could in the future be extended in areas such as parallel cables and connections of production facilities such as solar parks.

  • 73.
    Araya, Abel Russom
    et al.
    University West, Department of Engineering Science.
    Aden, Mohamud Abdullahi
    University West, Department of Engineering Science.
    Best Practice enligt ramverket ITIL: en studie om ITIL i praktiken2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    We conduct dissertations on the investigation of routines, models and systems on how companies and organizations should use IT operations. One of the systems is ITIL (Information Technology Infrastructure Library). As we do research on, how it works in practice in the workplace and whether there is a difference between companies. There are others such as Devops (Software development and IT operation), Agil, Scrum, ISO / IEC standards, Practical guide for policy analysis etc.

    Today, there are many different established methods, standards, models and routines for how companies and organizations should use IT operations. There are many systems that are process oriented for how companies and organizations conduct IT operations and support. One of the systems is ITIL (Information Technology Infrastructure Library). ITIL consists of five books that together form a framework for how to conduct management, operation and support in a process oriented manner.

    This thesis is based on a study of how ITIL is structured and how relevant it is today through research / interviews with various organizations that have adopted the framework specifically for ITIL's sub-processes problem management, access management and incident management. If it is experienced positively and is adaptable where previous surveys show that the implementation of ITIL has not fully worked on operations.

    We have investigated and focused more closely on some of ITIL's sub-processes Access, Problem and Incident Management. The ITIL framework that a collection of best practices can use during the implementation of IT operations. According to the results, ITIL has quite a large impact on the various operations. The effect it has on the operations is that after adapting this framework, the operations could have a better, more efficient and structured way of working.

    The framework is useful and helpful for the businesses as they do not have to invent their own methods or processes to get started, but they have the framework as method support, and they can work effectively. ITIL is too complex, and the organizations cannot make full use of the framework and more knowledge and time is needed to be able to complete the implementation of the framework, but this is also a resource issue for many organizations. However, you have your own solutions for the parts that you have not chosen to implement from the framework, which benefits the organization based on their needs. It is simply considered and said that we are satisfied with these parts and do not need to bother our staff or the business with implementing other parts.

  • 74.
    Arbo, Thomas
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    YubiKey: Utvärdering av tvåfaktorsautentisering2019Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    YubiKey is a small hardware method of authentication, designed to authenticate a user on various network-based platforms such as Google, Dropbox, Facebook and Twitter.

    In the first part of this paper, the underlying technology of the YubiKey, such as the one-time password protocol (OTP) and the Universal 2nd Factor standard, is further described, as well as the approach of the tests to examine how practical and secure the method itself is, but also examines its ease of use. These tests were performed on the platforms Google Account, Facebook, Dropbox and Twitter platforms. The YubiKey is also compared to other methods in relation to the phishing, malware, password guessing, man-in-the-middle and shoulder surfing attacks.

    The purpose of the comparison was to see if YubiKey protects against these attacks, compared to other methods, thus investigating its security. A later part presents the results of the tests, but also compares YubiKey with other methods in the market, and examines the recovery of a stolen och lost Yubikey. These tests show the simplicity of the method, its ease of use and how practical the method is.

    The comparison clearly shows that YubiKey is a very safe method, which resists common threats to the user side. The simulation of the recovery process further attests to its ease of use and ease of handling, even with lost or stolen key.

  • 75.
    Ardstål, Linus
    et al.
    University West, Department of Engineering Science.
    Starborg, Mikael
    University West, Department of Engineering Science.
    Oskärmad vs skärmad nätverkskabel; Hur stor skillnad gör det egentligen?2023Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

    UTP (Unshielded Twisted Pair) och STP (Shielded Twisted Pair) är två typer av kablar som används för att överföra data över ett nätverk. Båda typerna av kablar används för liknande ändamål, men de har vissa skillnader som kan vara betydande i vissa distributions scenarier. I småskaliga distributioner kanske UTP- och STP-kablar inte har någon signifikant skillnad i prestanda eller tillförlitlighet. Detta beror på att kablarna i ett litet nätverk vanligtvis inte behövs för att överföra data över långa avstånd eller i miljöer med höga nivåer av Electromagnetic Interference (EMI).UTP-kablar består av par med tvinnade ledningar, utan skärmning runt ledningarna. De är vanligtvis billigare än STP-kablar och enklare att installera eftersom de är lättare och mer flexibla. UTP-kablar används ofta i småskaliga distributioner som hem, små kontor och klassrum. I småskaliga distributioner kanske fördelarna med STP-kablar inte är nödvändiga, eftersom avståndet över vilket kablarna behöver överföra data vanligtvis är kort och det finns mindre risk för störningar. Dessutom kan UTP-kablar ge tillräcklig prestanda och tillförlitlighet för de flesta småskaliga nätverk. Vår metod för att introducera störning är att vira en lång UTP-kabel runt många strömkablar och tillhörande kopplad utrustning samt runt en stark strömkälla, en mikrovågsugn, för att se om dessa representationer av lågstörningsmiljöer är tillräckligt för att störa trafiken, trafiken mäts med iperf3 och Ubuntus egna felrapportering.Resultatet blev att nej, dessa scenarion var otillräckliga för att skapa någon nämnvärd störning av trafiken, mer efterforskning behövs och ännu starkare källor av störning bör tillämpas för att kunna se om det blir någon påverkan på trafiken med dessa mätmetoder.Detta innebär att i alla vardagliga scenarion är skärmad kabel helt överflödig och bör undvikas, en besparing både ekonomiskt och resursmässigt.

  • 76. Arezoomande, Daniel
    Anslutning av två vindkraftverk till befintligt nät2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis was conducted at University West in Trollhättan and Kungälv Energi AB in Kungälv. Being owner of an electrical grid, Kungälv Energi AB has the responsibility to check if the electrical grid needs to be reinforced when connecting new electricity generation facilities such as two new wind turbines. This thesis mission is to examine how the voltage quality might be affected by the connection of the wind turbines and give suggestions on how to solve eventual problems. Several alternatives will be examined for how the cables between the wind turbines and the power grid should be placed. One cost calculation will be presented. The voltage quality calculations are done through the guidelines from AMP, Anslutning av Mindre Produktionsanläggningar. Because the provider of the wind turbines has yet to be decided, necessary data has been taken from the previously connected wind turbine in Skåreby, "Vindrosen". The cost calculations are done with the help of EBR, ElByggnadsRationalisering. The cable dimension alternatives that are presented are based on costs and long term planning. These dimensions are 95mm2 and 240 (underground transmission line)- alt. 241mm2 (overhead transmission line). The thesis also includes suggestions for alternative dimensioning of the currently placed power grid at the point of interconnection for the wind turbines. All presented alternatives of the dimensioning for the cables are solely 24kV in accordance with the rest of the power grid to avoid unnecessarily high costs. It is recommended that Kungälv Energi AB does not connect the wind turbines before more thorough calculations are made in conjunction with eventual harmonic distortion measurements. This is because the equations AMP refers to are deemed imprecise due to some parameters such as cable capacitance have not been taken into consideration. It is recommended that, during the negotiations of the new wind turbines, Kungälv Energi AB limits the maximum current harmonic distortions that the wind turbine produces.

  • 77.
    Arezoomande, Daniel
    University West, Department of Engineering Science.
    Condition based maintenance of electrical motors in the mining industry2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This project aims to present a condition-based maintenance algorithm for common motor faults on three-phase induction motors in the mining industry through the use of the E300 overload relay. To fulfil this aim establishing what motor faults are common and which ones are suitable for detection based on electrical signal monitoring was explored. Through investigative research no distinction between common motor faults in general and those in the mining industry was discovered. A number of electrical signals candidates were chosen based on limited available research and consulting with experts in the field. To test these signals a number of phase to phase motor faults were physically simulated on a test rig. The resulting trend of the signals were saved and comparatively analyzed with a regular mechanical motor overload to find deviations that would indicate the fault has occurred.

    The most useful monitored signal was the current imbalance and the line current measurements. Through monitoring these signals it was concluded that the one phase-pair fault and the two phase-pair fault could be discovered by monitoring real-time values. The three phase-pair fault could not be discovered by monitoring the real-time values, but can be found trough historical trends of the line currents and current imbalance. 

    A condition-based maintenance algorithm was proposed utilizing the monitored electrical signals to create trends that can be tied to alarms. A general motor health index that would use the monitored signals to easily convey the health of the motor is proposed. A faceplate design for the Panelview 5510 was designed showing the trends of the various electrical signals that would be used by an operator in the field.

  • 78.
    Aronsson, Andreas
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Bäversjö, Jonathan
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning av gratis WiFi i Göteborg2014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report examines a number of free WiFi-hotspots that are offered by various companies in central Gothenburg and how they compare to the mobile networks. Traffic, capacity, channel frequencies, signal strength and acceptable use policies were all analyzed and verified.

    The readings showed that the networks were generally not utilized to their full capacity, a probable cause might be the distribution of mobile networks and that channel distribution was with a few exceptions allocated correctly according to 802.11 standards. Acceptable use policies on the networks were implemented by the larger chains but not by the smaller companies

  • 79.
    Ashok Kumar Prasanna Kumari, Athira
    University West, Department of Engineering Science.
    Discrete Event Simulation of the Paint shop at VBG Truck Equipment: A method for Work shift Optimization and Balanced Production flow2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The background for this thesis work emanates from a desire to drive the production of the VBG Truck Equipment factory in Vänersborg a step further to catch up with the Industry 4.0 standards. Discrete Event Simulation (DES) is a widely adopted tool within industries to model real-world systems to improve their processes. The concern of bottlenecks is a vital problem in optimizing and improving the efficiency of production processes. Finding and investigating bottlenecks is one of the primary considerations of all manufacturing industries.The company aims to enhance its logistics by using automation in its processes. This work focusses on the Paint shop part of the VBG factory. Thus, the VBG would like to analyse the methods to reduce the bottlenecks and the waiting time in the Paint shop production process. There were no simulation models available to analyse the existing paint shop pro duction flow; therefore, a Discrete Event Simulation (DES) model of the VBG Paint shop was built to investigate the bottlenecks and improvement methods.

    In this thesis work, the DES model of the existing Paint shop that uses the Last in First Out (LIFO) method was investigated to find the throughput and lead time for the products. In comparison, a First in First Out (FIFO) method was used to get a balanced production flow, and its effects were studied. The company currently uses two shifts in their Paint shop, so the alternate arrangement of shifts using the same number of operators was analysed. The analysis of three shifts with the same number of operators gave more efficiency than the existing one, and three shifts with an increasing number of operators were also compared. The shift arrangements were compared with both the LIFO and FIFO methods, and FIFO provided more throughput and balanced production flow.

    The main bottleneck was identified in the forklift transport waiting time, so an alternate layout using a power and free conveyor system was developed. This alternate arrangement reduced the bottlenecks and produced an increased output. The alternate layout was also compared with LIFO and FIFO methods; FIFO was the most efficient one. The shift patterns were also analysed, and the three shifts with a 50 percent increase in staff can reduce the stock build-up during the start of the first shift. As of this study, it was identified that the alternate model with FIFO is the most suitable solution for the company, and in the coming years, they intend to implement that. From the experimental results obtained, DES can be chosen as a method to analyse the problems associated with limiting the capacity of production. The DES modelling can be extended to the other processes in the factory and can be used for improving logistics and inventory management. The company production flow can be further advanced by evaluating the changes that can be implemented in the factory with real-time data.

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  • 80.
    Atar, Mohammad
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Förstudie till fältbusslaboration för elkraftstillämpningar2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis describes how to develop a fieldbus lab. The lab will be part of the course Data communications with electric power applications (course code DML200) at University West. The goal and purpose of this lab will be to allow students learn how to set up, commission and troubleshoot equipment. In this context, the course also directed towards electric power technology and it is important for the Bachelor programme in electrical engineering with specialization in power electric because the course is included in the program.

    The work was aimed at developing suitable equipment which must include the appropriate number of protection relays and the necessary components for communication via ProfiBus such as PLC controllers, I/O-module, the Operation Panel. Different companies where asked about the prices of the components and a collection of quotations was made.

    The response from three out of five different companies indicated that ProfiBus is an old system. Everyone wondered why ProfiBus was chosen as a communications system over other system such as Ethernet with ModBus. According to these companies ProfiBus is an old communication system and it is expensive. It could save some money if the problem was solved with ethernet with ModBus because of the availability of the manufacturers. Finally the lab idea was illustrated with a wiring diagram.

  • 81.
    Augustsson,, Jimmy
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Printz, Kristoffer
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Svensson, Erik
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Larmanalys för Vattenfall Vattenkrafts produktionsanläggningar längs Göta Älv2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Vattenfall Vattenkraft AB owns 57 large scale hydro power plants in Sweden with installed power exceeding 10 MW. The study relates to four of the plants located along Göta river. This report analyzes incidents and the related remedial actions that have occurred during the period 2014 – 2017 as well as the alarm and control systems with the aim to identify potential improvements. The incidents are categorized by error, what actions have been undertaken to correct the issue, plant and season. The incidents have predominately originated in the turbine and generator facilities and have been caused by abnormal levels or temperatures. During summer and winter time, this is mainly due to variation in temperature and flow in the river. The four plants have caused a similar amount of alarms, which is interesting as there is a large variation in age. The analysis does not identify any reoccurring issues which were previously unknown to the company, but the authors recommends that an investigation is conducted to assess if eel screens should be installed for the cooling pumps of Lilla Edet. The alarms are generated in the plants and are sent to the control facility in Bispgården near Sundsvall, where the operator calls the local engineer on duty in Trollhättan. The engineer subsequently goes to the plant to access detailed information on the incidents from the local computers. This report examines the possibility to provide the engineer on duty with detailed information from the plant computer via VPN. This would be possible to implement but would require a detailed assessment of the security implications. The status of the alarm system have also been assessed as it have been modified and extended retroactively, and there is currently no comprehensive overview. The conclusion is that a review of the list of incident codes and their priority is recommended.

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  • 82.
    Augustsson, Per
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Mansori, Farsad
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Skapande av dynamiskt modellnät för analys av lasters beteenden vid nätstörningar2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor’s thesis is carried out on behalf of Vattenfall Eldistribution AB in Trollhättan. This work aims to make modelling of power grids for simulations, of load behaviour during perturbations, in PSS/E more effective. Modelling will be made more effective by means of programming, using the programming language Python, and also by allowing certain assumptions to be made about the grid. The idea for this work arose from a certain case, during which Vattenfall was tasked with investigating why voltage levels near an industry would not recover after a short circuit, on the transmission line feeding the industry, was cleared. Investigations demanded simulations of the disturbance to be carried out in PSS/E, to describe what had happened. To enable simulation and to make it representative, the grid and its components must be adequately modelled. Svenska kraftnät has the data nessecary for such modelling, but it is inaccessible due to confidentiality. Due to the data being confidential extensive work with modelling was nessecary. Early simulations were based on the idea that some parts of the grid can be modelled using only simplified models, and with typical, or default, values. This thesis uses that hypothesis in the programming code. The low voltage after these perturbations were caused by motors, more specifically induction motors, drawing high currents from the grid during reacceleration when the voltage starts to recover after the perturbation. This high, and mostly reactive, current causes significant voltage drops across the lines and transformers, in turn causing other motors to draw more current and further lowering voltage. The programming code, called a script, developed during this work allows the user to quickly create dynamic model data to use when conducting simulations of the dynamic behaviour of this type of loads. Modelling of the generators is done quickly thanks to the assumption that generators are located far enough away that they are barely affected by the studied disturbance. They are, for this reason, modelled using typical values. Through a graphical interface, the user then select which loads to model. For each load model, the distribution across different types of loads is specified by the user. Finally, protection relays are modelled to enable current monitoring. The script has been tested by comparisons to a reference network model created by Vattenfall. The comparisons show minor deviation between the script and the reference. This could be because the script uses default values and models less components than the reference.

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  • 83.
    Augustsson, Svante
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Human and Robot Interaction basedon safety zones in a shared work environment2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The work explores the possibility to increase the automation along a production line by introducing robots without reducing the safety of the operator. The introduction of a robot to a workstation often demands a redesign of the workstation and traditionally the introduction of physical safety solutions that can limit the access to the work area and object on the production line. This work aims to find a general solution that can be used not only in the construction industry, but also in other types of industries to allow for an increased Human and Robot Interaction (HRI) without physical safety solution. A concept solution of a dynamic and flexible robot cell is presented to allow for HRI based on safety zones in a shared work environment. The concepts are based on one robot and the usage of a 3D camera system allowing for the design of virtual safety zones, used to control the HRI. When an operator approaches the robots work area and triggers a safety zone the robot stops its work and moves away from the operator. Based on the safety requirements and triggered zones the robot will continue to work in a new area or wait until the operator leaves the work area and then continue with the interrupted work task. This will allow the operator and the robot to work together, where the operator location controls the robots workspace. Testing and validation of the presented concept showed that the wanted functionality could be obtained. It also showed limitations to the equipment and the system used during tests and raised additional aspects of the safety for HRI. Of the detected limitations the most crucial when looking at up-time for the production line, is the camera system need of a relatively dust free environment, good and constant lighting. For the safety of the system the limitation lies in the size and placing of the safety zones in combination with the disturbance from  surrounding equipment. The presented concept has proven to work, and can be applied not only for the construction industry but for all industries with manufacturing alongside production lines with large components.

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  • 84.
    Augustsson, Svante
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Human and robot interaction based on safety zones in a shared work environment2014In: HRI '14: Proceedings of the 2014 ACM/IEEE international conference on Human-robot interaction, New York: Association for Computing Machinery (ACM), 2014, p. 118-119Conference paper (Refereed)
    Abstract [en]

    In this paper, early work on how to implement flexible safety zones is presented. In the case study an industrial robot cell emulates the environment at a wall construction site, with a robot performing nailing routines. Tests are performed with humans entering the safety zones of a SafetyEye system. The zone violation is detected, and new warning zones initiated. The robot retracts but continues its work tasks with reduced speed and within a safe distance of the human operator. Interaction is achieved through simultaneous work on the same work piece and the warning zones can be initiated and adjusted in a flexible way.

  • 85.
    Augustsson, Svante
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Olsson, Jonas
    University West, Department of Engineering Science, Division of Manufacturing Processes. University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    How to Transfer Information Between Collaborating Human Operators and Industrial Robots in an Assembly2014In: Proceedings the NordiCHI 2014: The 8th Nordic Conference on Human-Computer Interaction: Fun, Fast, Foundational, ACM Publications, 2014, p. 286-294Conference paper (Refereed)
    Abstract [en]

    Flexible human-robot industrial coproduction will be important in many small and middle-sized companies in the future. One of the major challenges in a flexible robot cell is how to transfer information between the human and the robot with help of existing and safety approved equipment. In this paper a case study will be presented where the first half focus on data transfer to the robot communicating the human's position and movements forcing the robot to respond to the triggers. The second half focuses on how to visualize information about the settings and assembly order to the human. The outcome was successful and flexible, efficient coproduction could be achieved but also a number of new challenges were found.

  • 86.
    Aw, Cheikh
    University West, Department of Engineering Science.
    Programming a robot arm using teaching method by using machine vision and sensor technology2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The use of robot has a major part in all kinds of industry (food, textile, automobile, agriculture, space and so on). With the increase of robot in industry, robot programming is also becoming more and more important, and more complex, therefor not accessible to anyone. The common way to program robot is by using programming languages, to communicate with the robot and its different element, and simulation, to observe the robot behaviour in a simulated environment before using a tangible one. Programming languages can be tedious, especially robot programming, which means that it can only be done by someone with the proper knowledge and education, making robot programming almost impossible to understand for non-robot programmers. To tackle this issue, a simpler programming method has been implemented during this thesis work, by combining machine vision and sensor technology. The idea is to track, using machine vision movement of a human arm, and use sensors, in this case a gyroscope, to register the orientation of the arm. The conclusion of this work shows us that the method investigated and developed, could allow a user, to manipulate an industrial robot, without knowing anything about robot or robot programming. Although, this method can be enhanced, by recording the movement done by the user, so that it can reproduce it for different work, by using an accelerometer tomove the robot at the same speed as the human hand. 

  • 87.
    Axelsson, Daniel
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Olsson, Daniel
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Utvärdering av olika dynamiska lastmodeller i PSS/E2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor’s thesis has been performed for Vattenfall Eldistribution AB. The purpose of this work has been to create understanding of dynamic load models and clarify how they function and how they can be used. The aim has been to perform simulations on short circuits and motor starts for two different load models. A part of the work is also to describe the basic principles of the induction motor to create a connection between simulation and theory. The theory of the induction motor contains information about the electric induction that is the basic principle of the induction machine. It also contains the correlations between torque, speed, current and voltage and also a description of the equivalent electric circuit. The IMD program is a program connected to PSS/E and it has been used to create the model for the induction motor that has been used for the simulations. The simulations have been based on instructions from the advisor and instructions from the PSS/E manuals. Simulations have been run with two of the built-in load models in PSS/E, one general load model and one model for induction motors. Short circuits have been simulated on both models and motor starts on the induction motor model. Short circuits have been simulated with two different fault durations 0.15 and 0.4 seconds. Motor starts have been simulated with two different transformer sizes 1.5 and 3.0 MVA and three different values of the inertia time constant 0.7, 1.0 and 1.5 MWs/MVA. At short circuit the fault duration causes larger currents and longer recovery times for both load models. At motor start the size of the transformer, in MVA, and the inertia time constant affects the motors starting time. Larger transformer means shorter time because of lesser drop in voltage. A larger inertia time constant means longer time.  If only the size of the voltage drop is of interest and not the course of the event, the motors start admittance can be used instead.

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  • 88.
    Aydin, Faruk
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Jasem, Anas
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Batterier som reservkraft i lågspänningsnät med solceller2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor’s thesis is written as a case study where the intended purpose is to reduce emissions of fossil fuels from a diesel generator and to ensure that Trollhättan Energi AB's customers receive an uninterrupted electricity supply during island operation. This is done by replacing diesel generators with chargeable batteries. 

    The identified problem occurs when Trollhättan Energi AB uses a diesel generator in a substation where solar cells are also connected, and the solar cells produce more power thanthe costumers consume. This surplus power from solar cells will result in a disconnection of the diesel generator due to reverse power protection.

    The battery capacity would need to be relatively large to cope with all the possible scenarios. For the use of battery only, the study limits the time intervals between sunrise and sunset to reduce the need for larger battery capacity. However, outside this time interval, an ordinary generator with environmental fuel HVO 100 is assumed to be used in parallel and therefore two different battery capacities were examined. Capacity for the batteries are 245 kWh and 490 kWh, respectively.

    The method is to find a charging level for the batteries that can adapt to different seasons. Since the power consumption is not the same in June as in February, the battery charging level is different for the different months. The results of the study show that with a battery capacity of 245 kWh, Trollhättan Energi AB must contact the solar cell owner during island operation to avoid interruptions. The battery capacity 490 kWh can handle island operation at all time intervals for the risk of back power throughout the year without having to contact the solar cell owner.

    Buying a 490 kWh battery costs approximately 400 kSEK / year over 15 years. It is expensive and not profitable to solve the problem with the reverse power. In the future, however, if the battery price is lowered and the number of solar cell systems increases, it may become more profitable. The easiest and cheapest solution today is to order the owners of the solar cell systems to switch of the power production and then use a diesel generator, as today. In Trollhättan, the number of solar cell installations is increasing, and this means that in the future it might be a more significant problem for Trollhättan Energi AB. If several customers install solar cells and a spontaneous interruption occurs, it will be more challenging to contact and organize a solar cell switch-off with all costumers. Therefore, buying a battery might be a solution in the future.

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  • 89.
    Aziz, Hakar
    et al.
    University West, Department of Engineering Science.
    Linder, Jonatan
    University West, Department of Engineering Science.
    Visualization boards and their applications in manufacturing and daily management2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    With digitalization becoming increasingly more important in the way that companies can increase their efficiency by allowing the employees to see the production in the way of visualization. This thesis explores how the design and implementation of digitalized visualization board in the form of the Mevisio platform can help Sansera streamline their production. The data collection was performed through daily communication with the workers and qualitative interviews. The results gathered from the communication and interviews showed that there was a lot of unnecessary information. The machine operators only cared about how much they had produced and how much they would and that it should be as simple as possible. Another thing gathered from the interviews was that it was easy to make errors when they used to visualize everything on whiteboards and paper. The conclusion was that with the help of a digitalized visualization board tailored for their needs they could more easily pay attention to the problems that arise and decrease the risk of human errors.

  • 90.
    Babu, Challa
    et al.
    Audisankara college of engineering and technology, Department of electrical and electronics engineering, Gudur, A.P, India (IND).
    Kumar, D. Dinesh
    Audisankara college of engineering and technology, Department of electrical and electronics engineering, Gudur, A.P, India (IND).
    Kumar, K
    SV College of Engineering, Tirupathi, AP, India (IND).
    Reddy, K Jyotheeshwara
    Sree Vidayanikethan Engineering College, Tirupathi, A.P., India (IND).
    Ramasamy, Sudha
    University West, Department of Engineering Science, Division of Production Systems.
    Power Monitoring and Control System for Medium Voltage Smart Grid Using IoT2020In: IOP Conference Series: Materials Science and Engineering, IOP Publishing , 2020, Vol. 906, article id 12007Conference paper (Refereed)
    Abstract [en]

    This paper presents a power monitoring and control system for a medium voltage smart grid system. The smart grid interconnects the power sources between solar PV panel and 220V distribution network. This system consisting major components of inverters, measuring meters, solar charge controllers, relays, Arduino NANO and Raspberry Pi. The Current, power and energy readings are duly recorded. The Internet of Things (IoT) plays the vital role in the data communication between the sensors and electric power system. The voltage and current sensor data is used for the protection of power system network. In the traditional systems only the communication is uni-directional. The reliability of power supply is increased by used the bi directional network communication medium such as IoT. The tabulated results of voltage levels between 203.5V up to 212.8V shows the feasibility and effectiveness of proposed design. The proposed IoT model demonstrated the bidirectional communication from the sensors to the control unit and vice versa.

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  • 91.
    Bangalore Nagendra, Naresh Bhargav
    University West, Department of Engineering Science.
    Extraction of valuable feature data from 3D Digital model to provide input data for automated EV battery disassembling system2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The exponential increase in the use of Electric vehicles has a potential remark that there would be a massive count of EV battery packs reaching end of life. Such products being hazardous to environment, it is clearly proven to have processes to reuse or recycle the same. Northvolt AB leading Li-ion battery manufacturer in Europe is striving towards developing green battery technology. Besides being a leading industry to produce batteries, they have realised the need of recycling EV batteries at an early stage and developed a pilot-scale recycling plant now to close the loop of battery manufacturing. In pilot plant, the primary step to handle EOL EV batteries is to dismantle them in an automated manner. The present thesis work contributes towards developing the automated dismantling process to be more flexible and reliable in handling heterogeneous battery packs arriving from various car manufacturers. Out of many research works being carried out in the pilot setup, the current thesis work is focusing towards two key areas of product digitalization to obtain a digital model of real-world object and extracting data from a digital model to provide a data input to the control systems of automated disassembling process. This clearly eliminates the methods of lower-level programming of automated systems and saves time and resources involved in re-programming and increase flexibility in the process.

  • 92.
    Banous, Johannes
    University West, Department of Engineering Science.
    Utvärdering av laddningssystem för elfordon2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Electric vehicles are an important part of the transition towards a more sustainable transportation sector and to achieve the set climate goals, both globally and nationally. Car manufacturers are constantly working on developing various components to optimize their features, including charging and everything in between. At the same time, standards and requirements are set regarding the appearance of a charging system to counteract losses in the form of harmonics and reactive power. This work aims to perform measurements during the charging of various electric vehicles and plug-in hybrids to real-time monitor any harmonics up to the 40th order, to study the total harmonic distortion (THD) and power factor. A measurement box was constructed to carry out measurements at different current levels up to 16A, with different electric and hybrid cars, the charging was made both in single-phase and three-phase systems. Measured results were then compared with the harmonic requirements found in the standard SS-EN 61000-3-2. The results showed that both the Tesla Model 3 and BMW 330e do not meet the standard for charging, while the Volvo V90 and Volvo XC40 comply with the standard's requirements.

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  • 93.
    Baric, Velibor
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Mugisha, Arthur
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Elkvalitetsmätningar vid Högskolan Väst och kartläggning av hur elkvalitetsutredningar hanteras vid elnätbolag2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today voltage quality is important in society, and with the constant continuing development of new modern technological products also makes people more demanding market and its products. This report describes the regulatory requirements on power quality and describe how a power quality works in practice. A clear written guidance on electrical connectivity have been performed in order to get clear instructions on how to connect today's instruments. Measurement has been conducted at University West for 24 hours using the school's equipment and with the help of an experienced supervisor. Furthermore, the report will include what affects the power quality and the consequences that may occur when there is poor power quality in the electricity grid. A distinction has been made on three network companies in Sweden of different size. The three network companies are Vattenfall AB, Göteborg Energi Nät AB and Trollhättan Energi AB. The survey has been done through interviews with officers and electrical engineers. The reason for this limitation is performed to find out if there are any established routines on how network companies handle customer complaints and unsatisfied customers. In addition, the report will describe the differences and similarities how these tree network company handled customer complaints. After interview with electricity suppliers can be concluded that there are few costumer complaints/cases per year from customer to the electricity supplier given how many customers it has. The result for measurement on voltage fluctuations, harmonics and flicker shows accordance with standards accepted values and it can be stated that University West has strong network.

  • 94.
    Barrvik, Erik
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Hagman, Alma
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning av orsaker till komponenthaverier i uppsamlingsnätet till vindkraftparkerna Vettåsen och Mårtensklack2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to investigate why the cable terminations and power transformers in Wallenstam’s wind power plants, at Vettåsen and Mårkensklack, have broken down six times since December 2011, which was when they were first put into service.

    Power readings have been taken but there are no records for the times of the failures, which make it difficult to specify the failure source. However, from the readings that have been taken, there is nothing to indicate a cause for the failures. The transients are small and the proportions of harmonics are low. Since the instruments used to take the readings will only record up to 50th harmonics, a possible cause of failure could be high harmonics. Thunder storms, and cutovers in the power grid can probably be dismissed as sources of failure as well as manufacturing and installation faults.

    One proposal to remedy cable termination failures is to use geometric terminations which have been developed for grids with harmonics. Also, to reduce transients in the systems, surge arresters could be installed at the Vettåsen and Mårtensklack stations to ensure that the power quality can be monitored. The power readings need to be continued to specify the failure source

  • 95.
    Bassem Yehia, Khaled
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Abdowod,, Vahab
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Analys av indikatorerna AIT, AIF, SAIDI och SAIFI i lokalnätet2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Swedish Energy Markets Inspectorate (EI) is a regulatory authority for electricity, district heating and natural gas, where one of their tasks is to control the company's power distribution quality. A good electrical delivery reliability is determined on the basis of EI:s regulations and general advice in the publication EIFS 2013:1.

    Every year, the power distribution companies reports data to EI of the disturbances they have had in their networks, which is used to measure and analyse the electrical delivery reliability in the Swedish electricity grid. EI uses established indicators that describe the electrical delivery reliability of the distribution networks in Sweden. The indicators used today are named SAIDI and SAIFI, which are customer-weighted indices that describe the average interruption duration and the average interruption frequency for a specific network.

    In the beginning of 2019, EI will consider introducing two indicators to replace the current SAIDI and SAIFI indices, the indicators are being defined as AIT and AIF. According to EI, these indicators will be better than SAIDI and SAIFI as they take into consideration the customer's expected power consumption during the power outage.

    The purpose of this report is to investigate how the new indicators AIT and AIF affects the delivery reliability indicators in GENAB:s network, where these indicators are exercised on different types of networks and then compared. How the network can be made more efficient in the future by means of automation in the network is investigated based on the results on the indicators.

    From the results and investigations, it can be concluded that the transition to AIT and AIF will result in an increase of the indicator´s interruption time and the number of interruptions for customers per year in GENAB:s network.

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  • 96.
    Behzad Far, Shervin
    University West, Department of Engineering Science, Division of Production Systems.
    Digital Twin of Automation Line: Seamless Transfer2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Manufacturing and automation lines are getting expanded to include Digital Twins as stepstowards Industry 4.0. In this regard, apart from the issues that Digital Twin designers commonly experience during the process, implementing the virtual model on the real system while transferring the codes and data can be challenging as well. Using Digital Twin as part of the future laboratory facility of University West for the automation line at Production Technology Centre (PTC), it first needs to be tested on the real line to discover possible problems that future students might face. In this master thesis, these errors and faults are investigated to help the automation line staff and students avoid them by possible solutions.The assembly routine in the Digital Twin of the automation line was tested with an HMI using the OPCUA platform both in manual mode and automatic mode. The automation line was tested in manual mode by changing the function blocks which work with the real PLC. Moreover, the students can use the conversion table to understand the difference between the Digital Twin and its real entity function blocks. However, it can take much time for students to make their HMI and PLC code compatible with the automation line at PTC. As a result, suggestions are made, and attention to some minor details of the test procedure are emphasized. Although, due to the COVID-19 pandemic, and packed schedule of PTC staff, the automation line was not completely assembled and for safety reasons the automatic mode of the tests was withdrawn.

  • 97.
    Beissinger Bart, Andres
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Selektivplan för 40/20/10 kV transformatorstation2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project has been conducted on the behalf of Grästorp Energi with the main purpose of inspecting, controlling, and updating protection settings for a 40-kV station. Data has primarily been collected from Grästorp Energi ek.f´s GIS-system, MICKEL. Data has also been collected from the relay settings. Short-circuit current calculations in the network have been made in accordance with SS-EN 60909–0. Time current curves were created and proved by Excel charting tool. The project also details calculations that must be performed using Excel to calculate maximum and minimum short-circuit currents for transformer station. Using these currents as well as data collected over the network, a proposal for new relay protection settings has been developed. The results show that the existing settings exhibit some deficiencies and the appointed relay protection settings need to be reviewed before new settings can be implemented.

  • 98.
    Beissinger Bart, Andres
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Soto Vallejos, Nicolas
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Beredning av kabelnät i området Sjöhaga - Lerdala Gård2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The thesis describes a preparation work for Ellevio AB. The preparation work is supposed to rebuild the power grid in Sjöhaga - Lerdala in Skövde municipality with the aim to weatherproofing the local area network and increase the reliability. The project concerns all work on preparation such as contact with authorities and landowners involved in the project, in order to agree on where the new cables can be built. Field visits were conducted continuously during the project for an overview of the area and to plan possible cable stretches, as well as the best possible location for the network stations in agreement with the landowners. The preparation of the underground cable is carried out in four parts, part one is Sjöhaga - Melldala, part two is Melldala - Karlsfors, part three is Karlsfors - Dämman and part four is Dämman – Lerdala Farm. Part one will have a serial satellite network station with a 200kVA transformer and no local network preparation will take place at this stage. In part two Karlsfors will keep its current local distribution network and network station, part three will have an ELIT3 network station fitted with a 100kVA transformer. For part four, there will be an ELIT3 network station with 100kVA transformer and three cable cabinets. In addition to these parts, the possibility for a redundancy feeding between Karlsfors - Yttersöra was investigated. However, when this was perceived as not possible due to the environmental conditions, it was decided, on the recommendation of a supervisor at PSN Kraftkonsult, to be placed between Dämman - Björnsäter with a overhead cable on existing poles. The cost of the renewal amounts to 2.6 million SEK and 449 thousand SEK for the redundancy from Dämman to Björnsäter. Network stations are positioned in Melldala, Dämman and Lerdala Farm which also has three cable cabinets. The total cable length of the HV-system is 6.5 km and the LV-system is 1.70 km.

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  • 99.
    Ben Mabrouk, Amina
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Maalallah, Mustafa
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Utvecklingsarbete gällande metoder för beräkning av bortkopplad last vid automatisk förbrukningsfrånkoppling2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Vattenfall Eldistribution wishes to compile in real time which load that is available for disconnection via AFK (Load shedding) to avoid network collapse. This is done by implementing methods on Vattenfall's operating system to get an estimation of the load available for disconnection when AFK is activated.

    The purpose of the work is to create a summarized measurement value which, in real time, indicates how much load is available for disconnection with AFK in Vattenfall's network. This is to ensure that Vattenfall Eldistribution meets the requirements of SvKFS 2012: 1 during all hours of the year.

    The work is divided into two parts; one part to produce useful methods for obtaining the desired measurement values and another part for the implementation that has taken place in Vattenfall's operating system. These goals have been achieved by carrying out analyses and calculations of approximately one hundred stations containing AFK equipment that are located in three different zones in the electricity area SE3.

    Results are presented through a final overview, which is a fictitious picture of how it looks after implementation based on the methods developed in Vattenfall's operating system. In the resulting overview image, each station containing the AFK equipment is presented with a sum of the available active power for disconnection and each station is located under respective disconnection step.

  • 100.
    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.

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