Power distribution networks are recognized as the constituent part of power systems with the highest concentration of failure events. Even though the faults in distribution networks have a local effect when compared to the generation and transmission sides, major contingency escalation events are being more frequently reported from this section. The various aspects regarding the reliability and performance of distribution networks are identified as an important topic. Integration of new technologies, automation and increased penetration of distributed generation is expected to make improving and even sustaining high reliability standards a complex task.   This thesis presents developed approaches to quantify and analyze the complex correlated failure probabilities of different failure modes in distribution networks. A theoretical simulation model that relates to real world data to measure false tripping probabilities is developed and tested. More simplified approaches that utilities can exercise with readily available data in fault registers are also established.  Optimal configurations that could improve system performance and respective investment costs are analyzed and savings in system reliability at the cost of grid investments are modelled. The optimization helps in prioritizing the most critical investments by considering the system impact of reconfigurations focusing on meeting customer demands and respecting transfer capacities of weak links. The value of existing networks and willingness of the grid owner in investing can be integrated into suggestive alterations to assist decision making in planning and maintenance allocation.   The thesis makes both system specific and generalizable observations from detailed data collection from power utilities. The observations and results have potential in aiding future research by giving important understanding of the reliability impacts of network structures and of control and protection equipment. / Eldistributionsnätet är den del av elnäten som leder till flest kundarbrott trots att felhändelserna oftast är mycket lokala jämfört med händelse på genererings och transmissions sidan. Alltså identifieras de olika aspekterna beträffande pålitlighet och prestanda för distributionssystem som viktiga ämnen. Integration av ny teknik, automatisering och ökad penetration av distribuerad produktion förväntas göra förbättringar och rent av upprätthållande av höga tillförlitlighetskrav till en komplex uppgift.   Denna avhandling presenterar metoder för att kvantifiera och analysera de komplexa och korrelerade sannolikheterna för olika fellägen i distributionsnätet. En teoretisk simuleringsmodell baserrad på verkliga data för att mäta sannolikheter för felaktiga brytarkommandon utvecklas och testas. Mer förenklade tillvägagångssätt där elnätsföretag kan använda lättillgängliga data i felregister presenteras också. Optimala konfigurationer som kan förbättra systemprestandan och investeringskostnader analyseras och minskningar i systemets tillförlitlighet genom minskade kostnader för nätinvesteringar modelleras. Optimeringen bidrar till att prioritera kritiska investeringar genom att påvisa systemets inverkan av omkonfigurationer. Optimeringen tär hänsyn till kundernas krav och att bevara överföringsförmågan hos svaga länkar. Värdet av befintliga nät och villigheten hos nätägaren att investera kan undersökas som förslag, till ändringar, som stöd detta för beslut om planering och underhåll.   Avhandlingen gör både systemspecifika och generaliserbara observationer från en detaljerad datainsamling från elnätägare. Observationerna och resultaten har potential att hjälpa framtida forskning genom att ge en viktig förståelse för tillförlitlighetseffekter från nätverksstrukturen och från kontroll- och skyddsutrustning. / <p>QC 20171004</p>

Att mäta effektförluster hos switchad elektronik är mycket svårt med hjälp av elektrisk mätutrustning, framför allt när switchfrekvensen är hög. Sedan ett tiotal år tillbaka har dock den kalorimetriska mätprincipen, som ursprungligen kommer från kemins värld, blivit uppmärksammad i sådana sammanhang. En kalorimeter kan mäta effektförlusten från ett godtyckligt objekt och är därför passande vid mätning av switchförluster. Denna rapport handlar om tillverkningen av kammaren till en kalorimeter som är konstruerad för mätobjekt i effektklassen 50 till 100 W och som möjliggör effektmätningar med en noggrannhet som understiger 0,2 W. För att minimera effektförlusterna genom kalorimeterns kammarväggar, regleras temperaturen på dessa. Även kammarens inre lufttemperatur regleras för att undvika att den skenar iväg när den värms av mätobjektet. Rapporten beskriver bland annat kalorimeterkammaren på systemnivå, vilken onoggrannhet som kan härledas till bristerna i kammaren, samt hur regulatorerna har dimensionerats. / It is very difficult to measure switching losses, using electrical measuring instruments, especially at high switching frequencies. Calorimetric measuring methods have gained more and more attention over the last decade in the area of power loss measurements for switch mode power electronics. Calorimeters have been used by chemists for a long time and their main benefit is that they can measure the power losses from any object, which is why they are so suitable for measuring switching losses. This paper describes the construction of the chamber for a calorimeter, designed for measuring 50 to 100 W devices, with a possible accuracy of less than 0,2 W. To minimize the power losses through the walls of the chamber, their surface temperatures are regulated. The air temperature inside of the chamber is regulated as well, to provide it from overheating when heated by the device under test. This paper describes, for instance, the calorimeter chamber on a system level, the measuring errors related to the chamber as well as how the temperature regulators are designed.

This thesis has been executed at AB Volvo Advanced Technology and Research-Driver Environment &amp; Human Factors as a part of the FFI (Strategic Vehicle Research) project SICS (Safe Interaction Connectivity and State). It describes a study which examined if adding sound will reduce the visual distraction in menu interfaces. Two concepts have been studied in comparison to each other and to a baseline without sounds. The sound added to the interface was spearcons (time compressed speech sounds) and earcons (musical sounds). A simulator study was carried out containing 14 participants between the ages of 36-59 who had to, while driving, perform 6 different tasks that involved interacting with the interface menus. Results showed that the performed tasks caused much less visual distraction from the road while having the spearcons as assistance. The earcons results showed no improvement. / Detta examensarbete gjordes på AB Volvo Advanced Technology and Research på avdelningen Driver Environment &amp; Human Factors som en del av FFI (Fordonstrategisk Forskning och Innovation) projektet SICS (Safe Interaction Connectivity and State). Examensarbetet beskriver en studie som undersökte ifall addering av ljud till ett menygränssnitt bestående av visuella displayer hjälper förare att minska distraktionen från vägen. Två olika ljudkoncept har tagits fram och jämförs med varandra och med baskonceptet utan ljud. De två ljudkoncepten var spearcons (tidskomprimerat tal) och earcons (musikaliska ljud bestående av toner). En simulatorstudie med 14 personer mellan 36 och 59 år genomfördes. Studien gick till så att 6 olika uppgifter som involverade interaktion med gränsnitten skulle genomföras medan man körde en lastbilssimulator. Resultaten visade att när man assisterades av spearcons reducerades distraktionen medan earcons inte gav någon förbättring.

I dagens samhälle utvecklas tekniken snabbt, allt ska bli mindre och samtidigt ska mer funktioner byggas in. På grund av detta blir stora komponenter som toroidtransformatorer allt mindre önskavärda. Men går det att ändra designen till ett mindre switchat nätaggregat problemfritt? Denna rapport kommer gå igenom grundläggande teori för att förstå hur ett switchat nätaggregat fungerar, samt beskriva momenten i framtagningen av en prototyp. Rapporten tar även upp moment som beskriver hur mätningar av elektromagnetiska störningar genomförs. Vi kommer se att jag lyckas ta fram en fungerande prototyp som fungerar inom kravspecifikationen. Dock får man inte ut den sökta verkningsgraden, det finns alltså förbättringsmöjligheter. Men en prototyp är ett av de många stegen till en färdig produkt. / same time more functions need to get built in. Because of this is a big component like a torodial transformer is no longer desirable. But is it possible to change the design of a linear power supply to a switch mode power supply without any problems? This paper presents the basic theories of how switch mode power supplies work, together with a description of how an electronic prototype is developed. An introduction on how electromagnetic interference measurements are done will also be presented. We are going to see that a working prototype can be developed. But the target efficiency is not reached, there is need for improvement. But remember, a prototype is the first step to a finished product.

This is a report of our examination project in electronics carried out for Bofors Test Center in Karlskoga. The task was to construct an electronic devise for starting up different kinds of measuring systems in exact time during test sequences. The modules that are used today are old and unreliable. Our goal was to construct a prototype, which later on is supposed to be developed into a useful system.

Detta examensarbete har utförts på Örebro universitet och Västerdalarnas Mekaniska Industri AB (VMI) i Malung för Ehrlund Microphones.Ehrlund Microphones tillverkar mikrofoner med sin patenterade kapsel, som bland annat består utav ett triangulärt membran. Under examensarbetets tid var en ny mikrofonmodell under utveckling. Målet med examensarbetet var att bistå Ehrlund Microphones med utförandet av tester och mätningar, samt att komma med förslag till förbättringar på den nya konstruktionen. På VMI i Malung, där kapslarna tillverkas, finns ett mätlabb som är till för att mäta kapslarnas frekvenssvar. Mätutrustningen i detta labb har installerats och konfigurerats för den mätmetod som har tagits fram för att verifiera kapslarnas frekvensgång. Slutsatsen av undersökningen huruvida skyddsgallret påverkar mikrofonens frekvensgång, är att den volym luft som ryms innanför skyddsgallret har större betydelse för frekvensgången än vad den geometriska utformningen av gallret har. Med stor sannolikhet kommer den nya transistorbaserade mikrofonmodellen att ha ett bättre signal/brus-förhållande än vad som visas i detta arbete, eftersom testerna har utförts på en prototyp i utvecklingsskedet. / This degree thesis has been conducted at the University of Örebro and Västerdalarnas Mekaniska Industri AB (VMI) in Malung on behalf of Ehrlund Microphones. Ehrlund Microphones produce microphones with their patented capsule, containing a triangular membrane.During the course of this thesis, a new microphone model was under construction. The aim was to assist Ehrlund Microphones conducting tests, measurements and also coming up with ideas of how to improve the construction of the new microphone model. At VMI, where the capsules are produced, there is a lab designed to measure the frequency response of the capsules. The equipment in this lab has been installed and configured for the measurement method used, to verify the frequency response of the capsules. The conclusion of the examination whether the grille of the microphone influence the frequency response of the microphone in a noticeable way, is that the volume of air enclosed by the grille has greater influence on the frequency response than the shape of the grille. It’s most likely that the new transistor based microphone model will have an improved signal/noise-ratio, considering that the tests conducted in this essay were made on a prototype under development.

In this thesis, the potential of the gap discharge transducer is investigated as transducers in a time-of-flight gas flow measurement setup designed for harsh environments.In this thesis the gap discharge transducer is operated in two different modes, named spark discharge transducer and glow discharge transducer. The spark discharge transducer generates a spark over a gap while the glow discharge transducer generates a continuous glow discharge.Earlier studies show that the spark discharge transducer is very durable and a potent sound pulse emitter. This thesis continues these studies by incorporating the spark discharge transducer into a flow measurement system as a sound pulse emitter. Further more, the gap discharge transducer is investigated as a potential sound pulse receiver.As an emitter in a flow measurement system the spark discharge transducer was placed in a pipe with a variable flow in a laboratory environment. The transducer was set to generate sparks to create the sound pulse and standard piezoelectric receivers were used to capture the signal.As a receiver, the gap discharge transducer was tested in two experiments. In the first experiment the spark discharge transducer was placed in a vacuum chamber to test the dependence between breakdown voltage and pressure. The pressure change from a sound pulse might cause breakdown in the gap of the transducer if an initial voltage between the electrodes is set close enough to breakdown. The breakdown leads to a spark which can be used to determine when a sound pulse arrives. In the second experiment the transducer was set to generate a glow discharge. The glow discharge was then subjected to a sound source. The voltage and current of the glow discharge depends on the environmental conditions in the gap. Pressure changes from a sound pulse will then affect the air in the gap which in turn changes the voltage and current characteristics of the discharge. The change in voltage and/or current can then be used to determine when a sound pulse has arrived.The investigation shows that the spark discharge transducer is a potential sound pulse emitter in a flow measurement system and could be capable of determining a flow quite accurately. As a receiver, the spark discharge transducer show limited potential. The pressure change of a spark generated sound pulse requires the receiver to be set very close to the breakdown voltage. But that close to the determined breakdown voltage will very often cause the gap to breakdown spontaneously. The glow discharge transducer, on the other hand, show promising potential. The transducer is proven to be able to receive sound waves and has a sensitivity that is deemed compatible with the spark discharge transducer as a sound pulse emitter. / Godkänd; 2014; 20140917 (krikar); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Kristoffer Karlsson Ämne: Industriell elektronik/Industrial Electronics Avhandling: Gap Discharge Transducers in a Transit Time Flow Measurement System Designed for Harsh Enviroments Opponent: Professor Per Lunde, Department of Physics and Technology, University of Bergen, Norge Ordförande: Professor Jerker Delsing, EISLAB, Institutionen för System- och rymdteknik, Luleå tekniska universitet Tid: Måndag den 17 november 2014, kl 12:30 Plats: A1545, Luleå tekniska universitet

Radio measurement systems may have their performance significantly degraded due to environmental factors such as multipath, weather effects, and mechanical displacements. Characterization of these effects are therefore important in order to ensure functionality of the system. The characterization itself may also be the purpose of the system. This thesis contributes to the answer to the question of how to assess the effect of the environment on the propagation and reception of radio waves for three different applications.Traditionally the functionality of a radio measurement system has been assessed using either simulations assuming ideal conditions (e.g. free space) or measurements under controlled circumstances. There is no doubt that both these approaches are very useful when designing antennas and related hardware. In many applications it is also sufficient to assume ideal conditions and only use an a priori characterization. The applications considered in this thesis all operates in an environment that can be considered to be challenging. In these cases the environment needs to be taken into account in the design process of the system. Both simulations and measurement methods have been considered. The combination of electromagnetic simulation methods, such as the method of moments (MOM) or the partial element equivalent circuit (PEEC) method, with statistical methods, such as the Monte Carlo method, have been given special attention. The measurement systems considered, both for determining the performance of antennas and for detection of objects and transponders, are all assessed from a "challenging environment" point of view.The three application considered are multistatic radar using global navigation satellite systems (GNSS), measurement systems for antenna arrays in noisy conditions, and simulation of RFID systems with moving transponders. In the multistatic radar the focus is on detecting signals reflected in directions other than that of the primary reflection. The results shows that detecting these signals is possible even with the low signal levels involved. This is especially the case when reflecting objects are present which could scatter the signal in a specular way. By using the equivalent electric current method it is possible to estimate the complex far-field radiation pattern of antenna arrays even when the signals used have a low signal-to-noise ratio (SNR). This has been shown using simulation of a large antenna array and with measurements using a small array for GNSS receivers. When designing RFID systems it is important to be able to estimate the performance in terms of number of detected transponders with all movements of the transponders taken into account. This is possible by using a very simple model of the transponders (e.g. a magnetic dipole) in which case only one electromagnetic simulation is needed. This enables the use of the Monte Carlo method to take the random movements of the transponders into account using a low number of computations. The use of the PEEC method further enables a combined simulation of both the electromagnetic properties of the reader antenna and the electric functionality of the receiver circuit.Although the considered application are very different the obtained solutions are in many ways general. The fact that even the weak signals reflected in non-specular directions in a multi-static GNSS radar can be detected can be used in any application involving multi-path propagation or stray signals. The equivalent electric current method have here been considered for two radically different antenna arrays operating in a low SNR environment. Although the simulation approach chosen for the RFID simulations rely heavily on the simple magnetic dipole method it would work with any antenna at any frequency as long as the model of the antenna is sufficiently simple. / Godkänd; 2009; 20091106 (tore); DISPUTATION Ämnesområde: Industriell elektronik/Industrial Electronics Opponent: Professor Zvonimir Sipus, University of Zagreb, Kroatien Ordförande: Docent Jonas Ekman, Luleå tekniska universitet Tid: Torsdag den 10 december 2009, kl 10.00 Plats: D 770, Luleå tekniska universitet

Major societal challenges such as environmental sustainability, availability of energy and raw materials, and globalisation are creating new requirements for many actors in society. These new requirements relate to efficiency, flexibility, sustainability, and competitiveness. While these aspects have all been around for some time, and many systems have been locally optimised with regards to one or a few of these requirements, recent advances in communication and processing capabilities promise increased possibilities for connecting different parts of society, allowing optimal operation on a much larger scale. While industrial production systems have been controlled electronically for decades, the digitisation of market channels and consumer systems, together with the possibility to interconnect different production facilities, now allow for automated interaction along the whole supply chain from raw materials to end users.Simultaneously, increased demand for efficiency forces increased specialisation among actors, which with increased possibilities of interconnectivity, creates large enterprises of cooperating, specialised stakeholders. One of the major remaining obstacles for a widespread adaptation of more intelligent, more connected systems, able to deliver these envisioned results, is a coherent approach to the engineering and management of Systems-of-Systems involving very large numbers of devices and operating across several automation domains.For traditional automation systems there are established engineering procedures and numerous standards for engineering data, although most are focused on the static processes that have traditionally been the norm. For full integration with a digital society many of the existing automation systems will need significant modifications and as many automation systems are ageing and in need of replacement, a suitable solution to this may be a large scale migration to new automation solutions. The work presented in this thesis includes some new approaches and methodologies to utilise the existing engineering procedures and standards, while introducing some of the flexibility proposed by the emerging technologies. The major technical solutions presented consist of a structure way to organise connected systems and how they are related, regardless of engineering standards used to design their interactions, and an approach to allow configuration of heterogeneous systems through service interactions.Further contributions include an approach for migrating certain categories of existing industrial control systems to a service oriented architecture, as a basic outline for adaption of the next generation of automation systems in industry.Certain remaining challenges have been identified, which have to be addressed for a successful launch of widespread interconnected automation systems based on Internet of Things and associated technologies.

The use of low-power wireless sensors and actuators with networking support in in-dustry has increased over the past decade. New generations of microcontrollers, new hardware for communication, and the use of standardized protocols such as the Internet Protocol have resulted in more possibilities for interoperability than ever before. This in-creasing interoperability allows sensors and actuator nodes to exchange information with large numbers of peers, which is beneficial for creating advanced, flexible and reusable systems.The increase in interoperability has resulted in an increase in the number of possible attacks from malicious devices or users. For this reason, the use of encryption techniques to protect client and server communications has become mandatory. However, even with state-of-the-art encryption mechanisms, there is no protection that can control access to each particular service with fine-grained precision. The nodes within an industrial network of wireless sensors and actuators are resource-constrained embedded devices, and increasing interoperability therefore requires a higher level of computation capabil-ities. The nodes’ intrinsic limitations of memory and processing exert an adverse effect on power consumption and communication delays, resulting in a shorter battery life-time. Therefore, the standard computing solutions for Internet communications are not directly applicable, and new mechanisms to achieve security, scalability, dependability, interoperability and energy efficiency are needed.Sensor and actuator networks can transmit sensed data, but they also offer access to the actuators. Such accesses, presumably provided via services, require an access protection scheme. For this reason, the use of access control mechanisms is mandatory. Access control assists in the creation of customized services and access policies. These access policies can isolate access permissions to devices with different roles, such as production and maintenance.The main contribution of this thesis is a novel, efficient IoT framework for industrial applications, including design, implementation, and experimental validation. The frame-work includes features for communication protection, authentication, fine-grained access control, zero-configuration networking, and run-time reconfiguration. These technologies and their corresponding energy consumption data clearly demonstrate the feasibility of integrating a battery-operated IoT concept into a functional System of Systems. The provided data also pinpoint the most critical areas for improvement.