In Geräten und Anlagen des Stromnetzes werden Steckverbinder mit hoher Stromtragfähigkeit eingesetzt, wenn bewegliche Teile kontaktiert werden oder Betriebsmittel mit geringem Aufwand montier- und demontierbar sein müssen. Die elektrische Verbindung der Leiter wird dabei oft mit federnden Kontaktelementen realisiert. Die Kontaktelemente müssen als Teil der Strombahn während der Lebensdauer des Geräts den Betriebsstrom im Kiloampere-Bereich und im Fehlerfall bis zu einige Sekunden lang den eine Größenordnung höheren Kurzschlussstrom tragen. In der vorliegenden Arbeit wurden Rechenmodelle für die innere Erwärmung von Hochstrom-Kontaktsystemen im stationären Dauerbetrieb und im transienten Kurzschlussfall entwickelt. Das elektrische und mechanische Langzeitverhalten im Temperaturbereich (105…180) °C wurde experimentell mit stromdurchflossenen, fettgeschmierten Modellsteckverbindern, die regelmäßig getrennt und neu gesteckt wurden, untersucht. Modellerstellung, Rechnungen und Versuche wurden beispielhaft mit Kontaktelementen vom Typ Multilam durchgeführt. Kontaktelemente und Leiter bestanden aus versilbertem Kupfer. Für das stationäre Betriebsverhalten wurden die mit der analytischen Spannungs-Temperatur-Beziehung nach Kohlrausch berechneten Ergebnisse mit einem Erwärmungsversuch verifiziert. Die Temperaturdifferenz zwischen Kontaktelement und Leiter ist bei Standardanwendungen, wie in Schaltanlagen, mit ≤ 3 K sehr klein. Deshalb ist die Leitertemperatur als Zielgröße beim Dimensionieren der Dauerstrombelastbarkeit ausreichend. Bei Kurzschlussstrombelastung wurde im Kontaktsystem eine schnelle, räumlich unterschiedlich ausgeprägte Erwärmung numerisch berechnet. Leiter und Kontaktelement erwärmen sich kontinuierlich, wobei die mittlere Endübertemperatur im Kontaktelement aufgrund des kleineren stromtragenden Querschnitts eine Größenordnung höher ist. Die Kontakte führen bei 50 Hz-Wechselstrom aufgrund ihrer vernachlässigbaren Wärmekapazität 100 Hz-Temperaturzyklen aus. Dabei können die Maximaltemperaturen noch deutlich größer als die mittlere Temperatur der Kontaktelemente sein. Im Langzeitversuch waren nach 16 000 h Betriebszeit bei 180 °C und regelmäßigen simulierten Steckvorgängen die Verbindungskräfte noch genügend groß, um die elektrischen Anforderungen eines neuen Kontaktsystems zu erfüllen. Allerdings führte bei einer Betriebstemperatur von 105 °C ein thermisch instabiles Schmierfett zum vorzeitigen elektrischen Ausfall eines Teils der Steckverbinder. / Switchgear and devices for the power grid use high-power connectors if moving parts have to be contacted or equipment shall be easily mountable and dismountable. The electrical connection of the conductors is often realized by spring-loaded contact elements. As part of the main circuit, contact elements must carry the full operating current in the kiloampere-range for the entire service life of the device. In case of a fault, the short-circuit current, which is one order of magnitude larger, has to be carried for up to several seconds. In this thesis, calculation models for the inner temperature rise of high-power contact systems in steady-state continuous operation, as well as for the transient short-circuit load case were developed. Electrical and mechanical long-term performance in the temperature range from 105 to 180 °C was experimentally investigated with current carrying, grease-lubricated model connectors which were regularly unplugged and replugged. Modelling, calculations and experiments were exemplarily carried out with Multilam contact elements. Conductors and contact element consisted of silver-plated copper. The analytical voltage-temperature relation was used to calculate the steady-state performance; calculations were verified with a temperature-rise test. The temperature difference from contact element to conductors is very small (≤ 3 K) for standard applications like switchgear. Thus, it is sufficient to use the conductor temperature as a criterion for the design of the continuous ampacity of high-power contact systems. At short-time load, a fast spatially inhomogeneous temperature rise was numerically calculated. Conductor and contact element continuously heat up; due to the smaller current carrying cross section, median final temperature rise in the contact element is one order of magnitude larger than in the conductors. Because of their negligible thermal capacity, contacts perform 100 Hz temperature cycles at 50 Hz AC load; the maximum contact temperatures may be significantly higher than the median temperature of the contact elements. In the long-term test, after 16 000 h operating time at 180 °C and regular plugging operations, contact elements maintained enough joint force to meet the requirements of a new contact system. At 105 °C however, a thermally instable grease led to electrical failure of part of the connectors.

<p>This doctoral thesis presents new ideas and research results on control of marine electric power system.</p><p>The main motivation for this work is the development of a control system, power management system (PMS) capable to improve the system robustness to blackout, handle major power system faults, minimize the operational cost and keep the power system machinery components under minimal stress in all operational conditions.</p><p>Today, the electric marine power system tends to have more system functionality implemented in integrated automation systems. The present state of the art type of tools and methods for analyzing marine power systems do only to a limited extent utilize the increased knowledge available within each of the mechanical and electrical engineering disciplines.</p><p>As the propulsion system is typically consisted of the largest consumers on the vessel, important interactions exists between the PMS and vessel propulsion system. These are interacted through the dynamic positioning (DP) controller, thrust allocation algorithm, local thruster controllers, generators' local frequency and voltage controllers. The PMS interacts with the propulsion system through the following main functions: available power static load control, load rate limiting control and blackout prevention control (i.e. fast load reduction). These functions serve to prevent the blackout and to ensure that the vessel will always have enough power.</p><p>The PMS interacts with other control systems in order to prevent a blackout and to minimize operational costs. The possibilities to maximize the performance of the vessel, increase the robustness to faults and decrease a component wear-out rate are mainly addressed locally for the individual control systems. The solutions are mainly implicative (for e.g. local thruster control, or DP thrust allocation), and attention has not been given on the interaction between these systems, the power system and PMS. Some of the questions that may arise regarding the system interactions, are as follows: how the PMS functionality may affect a local thruster control, how the local thruster control may affect the power system performance, how some consumers may affect the power system performance in normal operations and thus affect other consumers, how the power system operation may affect the susceptibility to faults and blackout, how various operating and weather conditions may affect the power system performance and thus propulsion performance though the PMS power limiting control, how propulsion performance may affect the overall vessel performance, which kind of faults can be avoided if the control system is re-structured, how to minimize the operational costs and to deal with the conflicting goals. This PhD thesis aims to provide answers to such questions.</p><p>The main contributions of this PhD thesis are:</p><p>− A new observer-based fast load reduction system for the blackout prevention control has been proposed. When compared to the existing fast load reduction systems, the proposed controller gives much faster blackout detection rate, high reliability in the detection and faster and more precise load reduction (within 150 miliseconds).</p><p>− New advanced energy management control strategies for reductions in the operational costs and improved fuel economy of the vessel.</p><p>− Load limiting controllers for the reduction of thruster wear-out rate. These controllers are based on the probability of torque loss, real-time torque loss and the thruster shaft</p><p>accelerations. The controllers provide means of redistributing thrust from load fluctuating thrusters to less load fluctuating ones, and may operate independently of the thrust allocation system. Another solution is also proposed where the load limiting controller based on thrust losses is an integrated part of DP thrust allocation algorithm.</p><p>− A new concept of totally integrated thrust allocation system, local thruster control and power system. These systems are integrated through PMS functionality which is contained within each thruster PLC, thereby distributed among individual controllers, and independent of the communications and dedicated controllers.</p><p>− Observer-based inertial controller and direct torque-loss controller (soft anti-spin controller) with particular attention to the control of machine wear-out rate. These controller contribute to general shaft speed control of electrical thrusters, generators and main propulsion prime movers.</p><p>The proposed controllers, estimators and concepts are demonstrated through time-domain simulations performed in MATLAB/SIMULINK. The selected data are typical for the required applications and may differ slightly for the presented cases.</p>

This doctoral thesis presents new ideas and research results on control of marine electric power system. The main motivation for this work is the development of a control system, power management system (PMS) capable to improve the system robustness to blackout, handle major power system faults, minimize the operational cost and keep the power system machinery components under minimal stress in all operational conditions. Today, the electric marine power system tends to have more system functionality implemented in integrated automation systems. The present state of the art type of tools and methods for analyzing marine power systems do only to a limited extent utilize the increased knowledge available within each of the mechanical and electrical engineering disciplines. As the propulsion system is typically consisted of the largest consumers on the vessel, important interactions exists between the PMS and vessel propulsion system. These are interacted through the dynamic positioning (DP) controller, thrust allocation algorithm, local thruster controllers, generators' local frequency and voltage controllers. The PMS interacts with the propulsion system through the following main functions: available power static load control, load rate limiting control and blackout prevention control (i.e. fast load reduction). These functions serve to prevent the blackout and to ensure that the vessel will always have enough power. The PMS interacts with other control systems in order to prevent a blackout and to minimize operational costs. The possibilities to maximize the performance of the vessel, increase the robustness to faults and decrease a component wear-out rate are mainly addressed locally for the individual control systems. The solutions are mainly implicative (for e.g. local thruster control, or DP thrust allocation), and attention has not been given on the interaction between these systems, the power system and PMS. Some of the questions that may arise regarding the system interactions, are as follows: how the PMS functionality may affect a local thruster control, how the local thruster control may affect the power system performance, how some consumers may affect the power system performance in normal operations and thus affect other consumers, how the power system operation may affect the susceptibility to faults and blackout, how various operating and weather conditions may affect the power system performance and thus propulsion performance though the PMS power limiting control, how propulsion performance may affect the overall vessel performance, which kind of faults can be avoided if the control system is re-structured, how to minimize the operational costs and to deal with the conflicting goals. This PhD thesis aims to provide answers to such questions. The main contributions of this PhD thesis are: − A new observer-based fast load reduction system for the blackout prevention control has been proposed. When compared to the existing fast load reduction systems, the proposed controller gives much faster blackout detection rate, high reliability in the detection and faster and more precise load reduction (within 150 miliseconds). − New advanced energy management control strategies for reductions in the operational costs and improved fuel economy of the vessel. − Load limiting controllers for the reduction of thruster wear-out rate. These controllers are based on the probability of torque loss, real-time torque loss and the thruster shaft accelerations. The controllers provide means of redistributing thrust from load fluctuating thrusters to less load fluctuating ones, and may operate independently of the thrust allocation system. Another solution is also proposed where the load limiting controller based on thrust losses is an integrated part of DP thrust allocation algorithm. − A new concept of totally integrated thrust allocation system, local thruster control and power system. These systems are integrated through PMS functionality which is contained within each thruster PLC, thereby distributed among individual controllers, and independent of the communications and dedicated controllers. − Observer-based inertial controller and direct torque-loss controller (soft anti-spin controller) with particular attention to the control of machine wear-out rate. These controller contribute to general shaft speed control of electrical thrusters, generators and main propulsion prime movers. The proposed controllers, estimators and concepts are demonstrated through time-domain simulations performed in MATLAB/SIMULINK. The selected data are typical for the required applications and may differ slightly for the presented cases.

In this thesis, a new HVDC-based converter system for wind farms is investigated. It is based on a mutually commutated soft-switching converter system and provides a unique integrated solution for the wind turbine generator drive systems, the wind turbine interconnection, and the power conversion for HVDC transmission. In a wind farm, the mutually commutated converter system is a distributed system. A medium-frequency collection grid connects the converter station, equipped with a single-phase voltage source converter and a medium-frequency transmission transformer, with the wind turbines, each containing a cycloconverter and a medium-frequency distribution transformer. In this thesis, various system aspects regarding the application of a distributed mutually commutated converter system in a wind farm are investigated. Special attention is paid to the design of a medium-frequency collection grid that has an acceptable level of transient overvoltages, the design of medium-frequency transformers with suitable magnetic, electric and thermal properties, and the development of a strategy to commutate the voltage source converter during low power generation. In order to adapt the mutually commutated converter system for an application in a wind farm, it had to be further developped. Different carrier-based and space-vector oriented modulation methods have been investigated. It turns out that for any load angle there is a quasi-discontinuous pulse width modulation strategy that can produce the same pulse patterns as space vector modulation. In addition, a modulation strategy has been developed that allows to replace the IGBTs in the cycloconverter with cheap, robust, and reliable fast thyristors, despite their absence of turn-off capability. The feasibility of different modulation strategies for mutually commutated converter systems has been verified on a down-scaled prototype converter system with both IGBT- and thyristor-based cycloconverters. Finally, a feasible wind farm layout is proposed, which considerably reduces the energy generation costs for large winds farms distant to a strong grid connection point. As a consequence, the proposed solution may facilitate the establishment of remotely located wind farms. / QC 20100802

Maximum asset performance is one of the major goals for electric power distribution system operators (DSOs). To reach this goal minimal life cycle cost and maintenance optimization become crucial while meeting demands from customers and regulators. One of the fundamental objectives is therefore to relate maintenance and reliability in an efficient and effective way. Furthermore, this necessitates the determination of the optimal balance between pre¬ventive and corrective maintenance, which is the main problem addressed in the thesis. The balance between preventive and corrective maintenance is approached as a multiobjective optimization problem, with the customer interruption costs on one hand and the maintenance budget of the DSO on the other. Solutions are obtained with meta-heuristics, developed for the specific problem, as well as with an Evolutionary Particle Swarm Optimization algorithm. The methods deliver a Pareto border, a set of several solutions, which the operator can choose between, depending on preferences. The optimization is built on component reliability importance indices, developed specifically for power systems. One vital aspect of the indices is that they work with several supply and load points simultaneously, addressing the multistate-reliability of power systems. For the computation of the indices both analytical and simulation based techniques are used. The indices constitute the connection between component reliability performance and system performance and so enable the maintenance optimization. The developed methods have been tested and improved in two case studies, based on real systems and data, proving the methods’ usefulness and showing that they are ready to be applied to power distribution systems. It is in addition noted that the methods could, with some modifications, be applied to other types of infrastructures. However, in order to perform the optimization, a reliability model of the studied power system is required, as well as estimates on effects of maintenance actions (changes in failure rate) and their related costs. Given this, a generally decreased level of total maintenance cost and a better system reliability performance can be given to the DSO and customers respectively. This is achieved by focusing the preventive maintenance to components with a high potential for improvement from system perspective. / QC 20100810

Static synchronous compensation (StatCom) is an application that utilizes a voltage source converter (VSC) to provide instantaneous reactive power support to the connected power system. Conventionally, StatComs are employed for reactive power support only. However, with the integration of energy storage (ES) into a StatCom, it can provide active power support in addition to the reactive power support. This thesis deals with the integration of ES into StatComs. The investigation involves the following aspects: possible benefits for power systems, main circuit design, and control strategies. As the basis of the investigation, a control scheme is proposed for two-level VSCs. It is a novel flux modulation scheme combined with the well-known deadbeat current control. The current controller is capable of controlling the positive sequence, the negative sequence, and the offset components of the converter current. With flux modulation, all the three above-mentioned components of the bus flux are controllable. This differs from the conventional voltage modulation scheme, in which only the positive and negative sequence components of the bus voltage are controllable. The difference between the proposed flux modulation scheme and the voltage modulation scheme is investigated regarding saturation of transformers in the connected system during fault recovery. The investigation shows that by controlling the offset component of the bus flux, the transformer saturation problem can be mitigated to a certain extent. The possible benefits of the additional active power support of StatComs are investigated through several case studies. Different active power compensation schemes are proposed. First, active power compensation for sudden load changes in weak systems is investigated. The proposed control strategies are verified through computer simulations and through experiments in a real-time simulator. It is shown that with active power compensation, both the phase jumps and magnitude variations in the voltage at the PCC can be reduced significantly. Secondly, the power compensation of cyclic loads is investigated. The results show that the power quality at the connection point can be improved regarding both phase jumps and magnitude variations. In the third case study, the fault-recovery performance of an example system is investigated, showing that improved performance can be achieved by the additional active power support. ES devices such as capacitors, supercapacitors, and batteries exhibit considerable variation in the terminal voltage during a charging/discharging cycle. A direct connection of ES devices to the dc side of a VSC requires a higher voltage rating of the VSC. Thus, the cost of the VSC has to be increased. In this thesis, a dual thyristor converter topology is proposed to interface ES devices with the dc side of the VSC. First, a cost comparison is performed to compare the total cost of the whole system with and without the proposed interface topology. A cost comparison between various types of ES is also presented, providing a guideline for the choice of ES at energy levels where several alternatives exist. Then, the dynamics of systems with the proposed interface topology are investigated. Control strategies are proposed and verified by computer simulations. Two different control methods for the dual-thyristor converter are compared. / QC 20100819

<p>In this thesis, controllers for power oscillation damping, transient stability improvement and power flow control by means of a Controlled Series Compensator (CSC) and and a Dynamic Power Flow Controller (DPFC) are proposed. These devices belong to the group of power system components referred to as Flexible AC Transmission System (FACTS) devices. The developed controllers use only quantities measured locally at the FACTS device as inputs, thereby avoiding the risk of interrupted communications associated with the use of remote signals for control.</p><p>For power systems with one dominating, poorly damped inter-area power oscillation mode, it is shown that a simple generic system model can be used as a basis for damping- and power flow control design. The model for control of CSC includes two synchronous machine models representing the two grid areas participating in the oscillation and three reactance variables, representing the interconnecting transmission lines and the FACTS device. The model for control of DPFC is of the same type but it also includes the phase shift of the internal phase-shifting transformer of the DPFC.</p><p>The key parameters of the generic grid models are adaptively set during the controller operation by estimation from the step responses in the FACTS line power to the changes in the line series reactance inserted by the FACTS device. The power oscillation damping controller is based on a time-discrete, non-linear approach which aims to damp the power oscillations and set the desired power flow on the FACTS line by means of two step changes in the line reactance separated in time by half an oscillation cycle.</p><p>A verification of the proposed controllers was done by means of digital simulations using power system models of different complexities. The CSC and DPFC controllers were shown to significantly improve the small-signal- and transient stability in one four-machine system of a type commonly used to study inter-area oscillations. The CSC controller was also tested for 18 different contingencies in a 23-machine system, resulting in an improvement in both the system transient stability and the damping of the critical oscillation mode. </p>

<p>The Swedish electricity market was de-regulated in 1996, followed by new laws and a new regulation applied to the natural monopolies of electrical distribution systems (EDS). These circumstances have motivated distribution systems operators (DSOs) to introduce more comprehensive analysis methods. The laws, the regulation and additional incentives have been investigated within this work and results from this study can be valuable when developing risk methods or other quantitative methods applied to EDS. This tendency is not unique for Sweden, the results from a comparative study of customer outage compensation laws between Sweden and UK is for example included.</p><p>As a part of investigating these incentives, studies of the Swedish regulation of customer network tariffs have been performed which provide valuable learning when developing regulation models in different countries. The Swedish regulatory model, referred to as the Network Performance Assessment Model (NPAM), was created for one of the first de-regulated electricity markets in the world and has a unique and novel approach. For the first time, an overall presentation of the NPAM has been performed including description of the underlying theory as a part of this work. However, the model has been met by difficulties and the future usage of the model is uncertain. Furthermore, the robustness of the NPAM has been evaluated in two studies with the main conclusion that the NPAM is sensitive toward small variations in input data. Results from these studies are explained theoretically investigating algorithms of the NPAM.</p><p>A pre-study of a project on developing international test systems is presented and this ongoing project aims to be a useful input when developing risk methods. An application study is included with the approach to systematically describe the overall risk management process at a DSO including an evaluation and ideas of future developments. The main objective is to support DSOs in the development of risk management, and to give academic reference material to utilize industry experience. An idea of a risk management classification has been concluded from this application study. The study provides an input to the final objective of a quantitative risk method.</p>

The introduction of performance based tariff regulations along with higher media and political pressure have increased the need for well-performed risk and asset management applied to electric power distribution systems (DS), which is an infrastructure considered as a natural monopoly. Compared to other technical systems, DS have special characteristics which are important to consider. The Swedish regulation of DS tariffs between 1996 and 2012 is described together with complementary laws such as customer compensation for long outages. The regulator’s rule is to provide incentives for cost efficient operation with acceptable reliability and reasonable tariff levels. Another difficult task for the regulator is to settle the complexity, i.e. the balance between considering many details and the manageability. Two performed studies of the former regulatory model, included in this thesis, were part of the criticism that led to its fall. Furthermore, based on results from a project included here, initiated by the regulator to review a model to judge effectible costs, the regulator changed some initial plans concerning the upcoming regulation.   A classification of the risk management divided into separate categories is proposed partly based on a study investigating investment planning and risk management at a distribution system operator (DSO). A vulnerability analysis method using quantitative reliability analyses is introduced aimed to indicate how available resources could be better utilized and to evaluate whether additional security should be deployed for certain forecasted events. To evaluate the method, an application study has been performed based on hourly weather measurements and detailed failure reports over eight years for two DS. Months, weekdays and hours have been compared and the vulnerability of several weather phenomena has been evaluated. Of the weather phenomena studied, heavy snowfall and strong winds significantly affect the reliability, while frost, rain and snow depth have low or no impact. The main conclusion is that there is a need to implement new, more advanced, analysis methods. The thesis also provides a statistical validation method and introduces a new category of reliability indices, RT. / Distribution av elektricitet är att betrakta som ett naturligt monopol och är med stor sannolikhet det moderna samhällets viktigaste infrastruktur – och dess betydelse förutspås öka ytterligare i takt med implementering av teknik ämnad att minska mänsklighetens klimatpåverkan. I Sverige finns det fler än 150 elnätsbolag, vilka är av varierande storleksordning och med helt olika ägarstrukturer. Tidigare var handel med elektricitet integrerat i elnätsbolagens verksamhet, men 1996 avreglerades denna; infrastruktur för överföring separerades från produktion och handel. Införandet av kvalitetsreglering av elnätstariffer under början av 2000-talet och hårdare lagar om bland annat kundavbrottsersättning samt politiskt- och medialt tryck har givit incitament till kostnadseffektivitet med bibehållen god leveranskvalitet. En viktig aspekt är att eldistribution har, jämfört med andra infrastrukturer, flera speciella egenskaper som måste beaktas, vilket beskrives i avhandlingens första del tillsammans med introduktion av risk- och tillförlitlighetsteori samt ekonomisk teori.  Två studier som kan ha bidragit till den förra regleringens fall och en studie vars resultat ändrat reglermyndighetens initiala idé avseende modell för att beräkna påverkbara kostnader i kommande förhandsreglering från 2012 är inkluderade.   Av staten utsedd myndighet övervakar att kunder erbjudes elnätsanslutning och att tjänsten uppfyller kvalitetskrav samt att tariffnivåerna är skäliga och icke diskriminerande. Traditionellt har elnätsföretag mer eller mindre haft tillåtelse till intäkter motsvarande samtliga omkostnader och skälig vinst, så kallad självkostnadsprissättning. Under slutet av 1990-talet började ansvarig myndighet emellertid arbeta mot en reglering av intäktsram som även beaktar kostnadseffektivitet och kundkvalitet. Vid utformande av en sådan reglering måste svåra avvägningar göras. Exempelvis bör elnätsföretags objektiva förutsättningar, såsom terräng och kunder, tas i beaktning samtidigt som modellen bör vara lätthanterlig och konsekvent. Myndigheten ansåg ingen existerande reglermodell vara lämplig att anpassa till svenska förhållanden, så en ny modell utvecklades: Nätnyttomodellen (NNM). För 2003 års tariffer användes denna och beslut om krav på återbetalning till berörda elnätskunder togs, vilka överklagades. En utdragen juridisk process inleddes, där modellen kritiserades hårt av branschen på flera punkter. Två, i avhandlingen inkluderade studier, underbyggde kritisk argumentation mot NNM. Beslut i första instans (Länsrätt) hade inte tagits 2008 då parterna kom överens avseende år 2003-2007. Ett EU-direktiv tvingar Sverige att gå över till förhandsreglering, och i stället för att modifiera NNM och fortsätta strida juridiskt för den, togs beslut att ta fram en helt ny modell. Nätföretagens tillåtna intäktsram kommer förenklat grunda sig på elnätsföretagens kapitalkostnader och löpande kostnader. Därtill, utifrån hur effektivt och med vilken kvalitet nätföretagen bedrivit sin verksamhet, kan tillåten intäktsram justeras.   En systematisk beskrivning av ett elnätsföretags nuvarande riskhantering och investeringsstrategier för olika spänningsnivåer tillhandahålles med syfte att stödja elnätsföretag i utvecklandet av riskhantering och att ge akademiskt referensmaterial baserat på branscherfarenhet. En klassificering av riskhantering uppdelat i olika kategorier och en sårbarhetsanalysmetod samt en ny tillförlitlighetsindexkategori (RT) föreslås i avhandlingen, delvis baserat på genomförd studie. Sårbarhetsanalysens övergripande idé är att identifiera och utvärdera möjliga systemtillstånd med hjälp av kvantitativa tillförlitlighetsanalyser. Målet är att detta skall vara ett verktyg för att nyttja tillgängliga resurser effektivare, t.ex. förebyggande underhåll och semesterplanering samt för att bedöma om förebyggande åtgärder baserat på väderprognoser vore lämpligt. RT är en flexibel kategori av mått på sannolikhet för kundavbrott ≥T timmar, vilket exempelvis är användbart för analys av kundavbrottsersättningslagars påverkan; sådana har exempelvis införts i Sverige och UK under 2000-talet. En statistisk valideringsmetod av tillförlitlighetsindex har tagits fram för att uppskatta statistisk osäkerhet som funktion av antal mätdata ett tillförlitlighetsindexvärde är baseras på.   För att utvärdera introducerad sårbarhetsanalysmetod har en studie utförts baserat på timvisa väderdata och detaljerad avbrottsstatistik avseende åtta år för två olika eldistributionsnät i Sverige. Månader, veckodagar och timmar har jämförts vars resultat exempelvis kan användas för fördelning av resurser mer effektivt över tid. Sårbarhet med avseende på olika väderfenomen har utvärderats. Av de studerade väderfenomen är det blott ymnigt snöfall och hårda vindar, särskilt i kombination, som signifikant påverkar eldistributionssystems tillförlitlighet. Andra studier har visat på sårbarhet även för blixtnedslag (som ej fanns med som parameter i avhandlingen inkluderad studie). Temperatur (t.ex. inverkan av frost), regn och snödjup har således försumbar påverkan. Korrelationsstudier har utförts vilket bland annat visar på ett nästan linjärt samband i Sverige mellan temperatur och elförbrukning, vilket indirekt indikerar att även elförbrukning har försumbar påverkan på leveranskvalitet. Slutligen föreslås ett analysramverk som introducerad sårbarhetsanalys skulle vara en del av. Övergripande idé presenteras, vilket främst skall inspirera för fortsatt arbete; emellertid bör påpekas att introducerad sårbarhetsanalysmetod är en självständig och färdig metod oavsett om föreslagna idéer genomföres eller ej. / QC 20110815

This diploma thesis entitled Design and realization of a mobile photovoltaic power plant is dividet into two parts. In the first, theoretical part one can learn about the state of representation of renewable energy sources in the field of electrical power engineering and about the structure of photovoltaic power station systems. The secont part of this thesis is focused on the own design and realization of the mobile photovoltaic power plant, on the selection of individual suitable components and ther dimensioning. In addition, a model of a mobile power plant has been created, on the basis of which the power plant was constructed. Finally, one can find a source code analysis of a power plant monitoring using a microcontroler