This master’s thesis is about earth fault locator testing on the model of unsymmetrical lines. The introductory part of thesis describes the function of the selected locator, mainly for the used calculation algorithm of fault location, options setting of fault locator and connection of the locator to the network. Master’s thesis in its practical part deals, with the setting fault locator for a particular test system on the model of the MV line and implementation of selected testing on the model unsymmetrical lines. The first part of the testing is focusing on verify the accuracy locator on an unsymmetrical line. The second test is then designed for obtaining the most accurate information on the distance of the fault, which fault locator can give. The final part is focused on verification algorithm for more accurate calculation of the fault location.

The future operation of public low voltage networks has to consider increased decentralised generation using photovoltaic systems for residential application. For utilities it is necessary to determine the maximum permissible installed power of residential photovoltaic systems in sections of the low-voltage network. For this purpose a method based on modelling low-voltage network structures, occurring loads and insolation situations is presented and demonstrated. The maximum permissible installed power of residential photovoltaic systems is fundamentally determined by the structure of the settlement of the affected low-voltage network section. By modifying the generator model the method can be applied too for other types of decentralized generators in the low-voltage network such as fuel cell systems. / Für den Betrieb des öffentlichen Niederspannungsnetzes in Wohnsiedlungsgebieten ist zukünftig mit einem verstärkten Einsatz dezentraler photovoltaischer Energiewandlungsanlagen zu rechnen. Für Netzbetreiber ist es erforderlich, die maximal zulässige Netzanschlussleistung derartiger Anlagen für Niederspannungs-Netzbezirke zu bestimmen. Dazu wird ein Verfahren auf der Grundlage der Modellierung der Struktur von Netzbezirken, der dort auftretenden Belastungen und Einstrahlungssituationen vorgestellt und demonstriert. Die maximal zulässige Netzanschlussleistung dezentraler photovoltaischer Energiewandlungsanlagen wird wesentlich durch die Siedlungsstruktur des betreffenden Niederspannungs-Netzbezirkes bestimmt. Durch Modifikation des Erzeugermodelles kann das Verfahren auch für andere dezentrale Kleinerzeuger im Niederspannungsnetz angewandt werden.

Exponering av det lågfrekventa ELF (Extremely low frequency) magnetfältet som genereras vid dagens elnät är något som är relativt nytt för människokroppen och den ökar ständigt i och med den tekniska utvecklingen. Eftersom det inte finns ett klart svar på hur fältet påverkar kroppen så tillämpas försiktighet för att hålla exponeringsnivåerna nere och försäkra sig om att ingen skada sker. Med hjälp av tidigare forskning inom området och uppmätta värden från olika anläggningar samt överslagsberäkningar har ett verktyg i Excel tagits fram för att kunna uppskatta magnituden av magnetfältet. Verktyget innehåller information om styrkan på magnetfältet från transformatorer, ställverk, elcentraler, kraftledningar och kanalskenor. Användaren skriver in ett antal parametrar för att få utdata om hur starkt magnetfältet är på olika avstånd ifrån källan. Detta presenteras i form av en tabell och en graf för respektive utrustning. Eftersom magnetfält alstras beroende på strömmens riktning, påverkar själva geometrin i olika elanläggningar magnetfältets styrka. För att beräkna exakta värden krävs då avancerade simuleringsprogram. Med detta verktyg kan projektörer redan vid ett tidigt skede uppskatta magnetfältet. / The exposure of ELF (Extremely low frequency) magnetic field generated by today’s electrical power system, is something that is relatively new to the human body and it is constantly increasing as more technology is developed. As there is no clear answer on how the field actually affects the body, a measure of caution is applied to ensure that the exposure levels are kept down to make sure no harm is done. With the help of previous research in the field, measured values from different locations and approximate calculations, a tool was developed in Excel to estimate the magnitude of the magnetic fields. The tool provides information about the magnitude of magnetic fields from transformers, switchgears, switchboards, powerlines and busbars. The user enters a number of parameters and the tool provides output data with the magnitude of the magnetic field at different distances from the source. This is presented in the form of a table and a graph for each equipment. Since the magnetic field is generated depending on the currents direction, the actual geometry of the electrical system needs to be taken in consideration when calculating the exact magnetic field. This requires an advanced simulation software to be accurate. With this tool, designers have the opportunity to estimate the magnetic fields at an early stage of development.

Exponering av det lågfrekventa ELF (Extremely low frequency) magnetfältet som genereras vid dagens elnät är något som är relativt nytt för människokroppen och den ökar ständigt i och med den tekniska utvecklingen. Eftersom det inte finns ett klart svar på hur fältet påverkar kroppen så tillämpas försiktighet för att hålla exponeringsnivåerna nere och försäkra sig om att ingen skada sker. Med hjälp av tidigare forskning inom området och uppmätta värden från olika anläggningar samt överslagsberäkningar har ett verktyg i Excel tagits fram för att kunna uppskatta magnituden av magnetfältet. Verktyget innehåller information om styrkan på magnetfältet från transformatorer, ställverk, elcentraler, kraftledningar och kanalskenor. Användaren skriver in ett antal parametrar för att få utdata om hur starkt magnetfältet är på olika avstånd ifrån källan. Detta presenteras i form av en tabell och en graf för respektive utrustning. Eftersom magnetfält alstras beroende på strömmens riktning, påverkar själva geometrin i olika elanläggningar magnetfältets styrka. För att beräkna exakta värden krävs då avancerade simuleringsprogram. Med detta verktyg kan projektörer redan vid ett tidigt skede uppskatta magnetfältet. / The exposure of ELF (Extremely low frequency) magnetic field generated by today’s electrical power system, is something that is relatively new to the human body and it is constantly increasing as more technology is developed. As there is no clear answer on how the field actually affects the body, a measure of caution is applied to ensure that the exposure levels are kept down to make sure no harm is done. With the help of previous research in the field, measured values from different locations and approximate calculations, a tool was developed in Excel to estimate the magnitude of the magnetic fields. The tool provides information about the magnitude of magnetic fields from transformers, switchgears, switchboards, powerlines and busbars. The user enters a number of parameters and the tool provides output data with the magnitude of the magnetic field at different distances from the source. This is presented in the form of a table and a graph for each equipment. Since the magnetic field is generated depending on the currents direction, the actual geometry of the electrical system needs to be taken in consideration when calculating the exact magnetic field. This requires an advanced simulation software to be accurate. With this tool, designers have the opportunity to estimate the magnetic fields at an early stage of development.

Physical asset management in the electric power sector encompasses the scheduling of the maintenance and replacement of grid components, as well as decisions about investments in new components. Data plays a crucial role in these decisions. The importance of data is increasing with the transformation of the power system and its evolution toward smart grids. This thesis deals with questions related to data management as a way to improve the performance of asset management decisions. Data management is defined as the collection, processing, and storage of data. Here, the focus is on the collection and processing of data. First, the influence of data on the decisions related to assets is explored. In particular, the impacts of data quality on the replacement time of a generic component (a line for example) are quantified using a scenario approach, and failure modeling. In fact, decisions based on data of poor quality are most likely not optimal. In this case, faulty data related to the age of the component leads to a non-optimal scheduling of component replacement. The corresponding costs are calculated for different levels of data quality. A framework has been developed to evaluate the amount of investment needed into data quality improvement, and its profitability. Then, the ways to use available data efficiently are investigated. Especially, the possibility to use machine learning algorithms on real-world datasets is examined. New approaches are developed to use only available data for component ranking and failure prediction, which are two important concepts often used to prioritize components and schedule maintenance and replacement. A large part of the scientific literature assumes that the future of smart grids lies in big data collection, and in developing algorithms to process huge amounts of data. On the contrary, this work contributes to show how automatization and machine learning techniques can actually be used to reduce the need to collect huge amount of data, by using the available data more efficiently. One major challenge is the trade-offs needed between precision of modeling results, and costs of data management. / <p>QC 20210330</p>

The main concern of this thesis is to design heating system for 5 storey apartment building in two alternatives of heat source - with a heat pump and with traditional gas boiler. Both applications are connected to two-pipes distribution system in building using the low-temperature water and radiators. The proposal takes account of the the production of hot water. The one of aims is to compare both variants also from the economic point of view. The experimental part is divided into two parts. The first part deals with the obligation to control efficiency of boilers, imposed by the Energy efficiency law No. 177/2006 Co. and § 6, sect. 2 - 5 and related regulation No. 276/2007 Co. The second part deals with the assessment of monitored room for proper regulation of the heating system.

This work examines the local distribution system in two residential areas in two Swedish towns, Oxelösund and Karlskrona, and studies how integration of PV systems and electric vehicle (EV) charging stations (CS) will affect the present distribution system. The research questions focus on the economic feasibility of a LVDC system, how it compares to a traditional LVAC (low voltage alternating current) system from an economic and technical perspective, and the possibilities a LVDC system brings to other DC component applications. The Swedish government aims to have a fossil-free vehicle fleet by 2030 and one of the measures is no fossil-fuel burning vehicle will be produced and sold in Sweden. This means the number of CS, and the charging infrastructure around these, need to be developed, to contribute to this goal and sustain this transformation. A connected issue is that updates on the regulations for non concession-regulated networks (IKN) in January 2022 extended the basic preconditions and allows possibilities for energy sharing between buildings. The new regulations are also in favor of micro-production and contribute to more decentralised systems. Connections of Renewable Energy Sources (RES) to the distribution system are expected to increase in the coming years. Grid-connected solar PV systems in Sweden have increased by 56% between 2019 and 2020, and at the same time EVs are becoming more apparent on the roads. These DC-(direct current) based technologies, and the possible need to strengthen local networks to accommodate new sources and loads, are bringing new opportunities for low voltage direct current (LVDC) based distribution systems. To answer the research questions, two different models with different concepts, parallel pure DC and parallel AC/DC, were built in simulation software. The conclusion of this study is that a traditional LVAC system is preferable over pure DC system from both economic and technical perspective for already connected areas, such as the two areas in this project. A parallel pure DC system might be preferable in newly built areas with substantial PV and EV, where exchange is wanted between buildings with separate AC grid connections. / Detta examnesarbetet undersöker det lokala distributionssystemet i två bostadsområden, i Oxelösund och Karlskrona. Arbetet fokuserar på hur (nya) anslutningar av solceller och laddstationer för elfordon (CS) kommer att påverka det nuvarande distributionsnätet i områdena. Forskningsfrågorna fokuserar på den ekonomiska genomförbarheten av ett LVDC-system, och hur det är jämfört med ett traditionellt LVAC-system (lågspänningsväxelström) ur ett ekonomiskt och tekniskt perspektiv, samt vilka möjligheter ett LVDC-system kan bidra med till andra DC-komponenttillämpningar. Den svenska regeringen ämnar ha en fossilfri fordonsflotta år 2030 och en av åtgärderna till målet är att sluta producera och sälja fossildrivna fordon i Sverige. Det innebär att antalet CS samt en laddingsinfrastruktur behöver utvecklas för att kunna bidra till målet och upprätthålla omställningen. De senaste uppdateringarna i regelverket för icke koncessionspliktiga nät (IKN) i januari 2022 vidgade de grundläggande förutsättningarna och bidrog till större möjligheter till energidelning mellan flera huskroppar. Det nya regelverket gynnar mikroproduktion och bidrar också till mer decentraliserade system. Anslutningar av RES till distributionsnätet förväntas öka under de kommande åren. Nätanslutna solcellsanläggningar i Sverige ökade med 56% mellan 2019 och 2020, samtidigt som det blir fler och fler elbilar på vägarna. Dessa DC-(likströms) baserade teknik kan öppna upp nya möjligheter för ett lågspänningslikström- (LVDC) baserad distributionssystem. För att besvara forskningsfrågorna byggdes två olika modeller med olika koncept, parallell ren DC och parallell AC/DC i simuleringsprogram. Slutsatsen av denna studien är att ett traditionellt LVAC-system är att föredra framför rent DC-system ur både ekonomiskt och tekniskt perspektiv för redan anslutna områden, som de två områdena i detta projekt. Ett parallellt rent DC-system kan vara att föredra i oanslutna områden, dvs nya bostadsområden under utveckling.

<p dir="ltr">Electric roadways (ERs) represent a new paradigm for electrified transportation that is</p><p dir="ltr">enabled by the emerging dynamic (in-motion) wireless power transfer technology. Large-scale</p><p dir="ltr">integration of DWPT systems into power grids can pose a problem due to its high-power</p><p dir="ltr">requirements, significant number of power electronic converters and spatial concentration.</p><p dir="ltr">Despite their potential magnitude, the operational impacts of DWPT on the power grid have</p><p dir="ltr">not been fully studied in the literature. This dissertation contributes to our understanding</p><p dir="ltr">of how ERs could be successfully integrated with the electric power system at a diverse range</p><p dir="ltr">of spatial and temporal levels.</p><p dir="ltr">On a macroscopic level, a framework for assessing the financial viability of ERs is proposed.</p><p dir="ltr">Annual ER load estimations from traffic flow models of electric vehicles are used to</p><p dir="ltr">generate energy forecasts and carry out a financial evaluation. These models are also used to</p><p dir="ltr">plan distribution system capacity expansion. On a mesoscopic level, a data-driven design of</p><p dir="ltr">ERs and their interconnection with the distribution grid is presented. A data-based stochastic</p><p dir="ltr">traffic flow model is developed and used for designing the interconnection of the DWPT</p><p dir="ltr">system with the distribution grid ensuring adequate power transmission to high penetration</p><p dir="ltr">levels of heavy-duty trucks. The model is also used for conducting a series of quasi-steady</p><p dir="ltr">state studies on the power distribution system. On a microscopic level, a methodology for</p><p dir="ltr">modeling ER systems for time-domain simulations is proposed. Dynamic component models</p><p dir="ltr">are developed for the DWPT system. Power electronics are modeled using average-value</p><p dir="ltr">representations and integrated with models of the distribution grid. The models are used for</p><p dir="ltr">time-domain system simulations, transient analysis, fault analysis and power quality studies.</p><p dir="ltr">Theoretical analysis as well as numerical case studies and simulations of the proposed</p><p dir="ltr">methodologies are presented.</p>

[pt] Os segmentos de geração, transmissão e distribuição constituem a cadeia produtiva do setor elétrico, sendo o consumidor ou carga o último elo que deve ser atendido pelas distribuidoras. A percepção de qualidade, e consequentemente a satisfação do cliente, está intrinsecamente relacionada, entre outros fatores, à continuidade do fornecimento assegurada pelas concessionárias. No Brasil, a Agência Nacional de Energia Elétrica (ANEEL) é responsável por regular o setor de distribuição e estabelecer indicadores de referência com o objetivo de avaliar a eficiência das concessionárias em termos de confiabilidade e qualidade do serviço prestado. Diversos fatores podem impactar a continuidade da distribuição de energia, sendo alguns mais conhecidos e gerenciáveis pelas empresas, como quedas de objetos na rede ou sobrecarga de equipamentos. No entanto, outros fatores, como restrições de acesso a determinadas áreas devido à violência e ao controle territorial por grupos criminosos, apresentam desafios complexos e de gerenciabilidade inexistente por parte das distribuidoras. Essas limitações dificultam a pronta recomposição do serviço em situações emergenciais, resultando em tempos de falha mais longos e afetando negativamente os indicadores de continuidade monitorados pela ANEEL, bem como a satisfação do consumidor. Neste contexto, a presente dissertação propõe uma metodologia focada em identificar os ativos da distribuidora localizados em áreas com evidências de violência, o que implica em acesso limitado pelas equipes de campo. É utilizada a base de dados geográfica da distribuidora (BDGD) para identificar as unidades transformadoras em áreas com evidências de violência, também delineadas por plataformas de dados públicos. Técnicas de clusterização e testes estatísticos são então utilizados para aferir se os índices de continuidade nessas áreas são significativamente diferentes e superiores aos de locais em que não se observa registros de violência. Sistemas de distribuição dos estados do Rio de Janeiro e Pernambuco são utilizados para testar a eficácia da metodologia proposta. Diversos testes são realizados e os resultados obtidos são plenamente discutidos. / [en] The segments of generation, transmission and distribution constitute the production chain of the electricity sector, with the consumer or load being the last link that must be served by the distributors. The perception of quality, and consequently customer satisfaction, is intrinsically related, among other factors, to the continuity of supply ensured by the concessionaires. In Brazil, the National Electric Energy Agency (ANEEL) is responsible for regulating the distribution sector and establishing benchmarks in order to assess the efficiency of concessionaires in terms of reliability and quality of service provided. Several factors can impact the continuity of energy distribution, some of which are better known and manageable by companies, such as falling objects on the network or overloading equipment. However, other factors, such as access restrictions to certain areas due to violence and territorial control by criminal groups, present complex challenges and non-existent manageability on the part of the distributors. These limitations make it difficult to promptly restore the service in emergency situations, resulting in longer failure durations and negatively affecting the continuity indicators monitored by ANEEL, as well as consumer satisfaction. In this context, this dissertation proposes a methodology focused on identifying the distributor s assets located in areas with evidence of violence, which implies limited access by field service teams. The distribution company s geographic database (BDGD) is used to identify transforming units in areas with evidence of violence, also delineated by public data platforms. Clustering techniques and statistical tests are then used to assess whether the continuity indices in these areas are significantly different and higher than those in places where there are no records of violence. Distribution systems in the states of Rio de Janeiro and Pernambuco are used to test the effectiveness of the proposed methodology. Several tests are carried out and the results obtained are fully discussed.

Fuel Cell Hybrid Electric vehicles are hybrid vehicles that consist of both fuel cells and batteries as energy conversion systems. The Energy Management System plays an important role in the operation of the fuel cell hybrid system, as it helps in reducing the hydrogen consumption of the system. This study investigates an optimal control algorithm with an aim to reduce the hydrogen consumption of the fuel cell system for five different drive cycles operating in Europe. Model Predictive Control(MPC) is used to solve the optimal control problem, by formalizing a look ahead controller, utilizing its receding horizon approach. The optimal controller analysis is compared with a conventional rule-based controller, by analysing the hybrid system over various battery and fuel cell sizes, on the basis of the overall hydrogen consumption. Firstly, a simplified system model is developed, by modelling the fuel cell system with respect to the efficiency curve of the hydrogen power and fuel cell power. The battery system model with its State of Charge(SOC) is coupled with the fuel cell model to form an objective function satisfying the power demand from the drive cycles. The MPC controller and the rule-based controller are implemented in MATLAB and the powersplit analysis is simulated for all five routes. The results show that the energy management system with the MPC controller optimizes the powertrain configuration efficiently, with preparing for the uphill or downhill, such that the battery SOC stays in its limits and the fuel cell operates in the most efficient range. This ensures operating over different types of drive cycles with the most efficient battery and fuel cell size, hence concluding with the MPC controller outperforming the rule-based one. / Fuel Cell Hybrid Electric Vehicle (FCHEV) är hybridfordon som består av både bränsleceller och batterier som energiomvandlingssystem. Energy ManagementSystem (EMS) spelar en viktig roll i driften av bränslecellshybridsystemet, eftersom det hjälper till att minska systemets vätgasförbrukning. Denna studie undersöker en optimal styralgoritm framtagen i syfte att minska syfte att minska vätgasförbrukningen i bränslecellssystemet. Algoritmen testas på fem olika körcykler, baserade på verkliga Europeiska vägsträckor. Model Predictive Controller (MPC) används för att lösa det optimala styrproblemet, genom att formalisera en framåtblickskontroller med hjälp av dess vikande horisont. Den optimala kontroller jämförs med en konventionell regelbaserad kontroller, genom att analysera hybridsystemet över olika batteri- och bränslecellstorlekar, baserat på den totala väteförbrukningen. Först utvecklas en förenklad systemmodell, som modellerar bränslecellssystemet med avseende på effektivitetskurvan för vätgaskraften och bränslecellseffekten. Batterisystemmodellen med dess State of Charge (SOC) är kopplad till bränslecellsmodellen för att bilda en målfunktion som tillfredsställer kraftbehovet från drivcyklerna. MPC-styrningen och den regelbaserade styrningen är implementerade i matlab och effektdelningsanalysen simuleras för alla fem rutterna. Resultaten visar att energihanteringssystemet medMPC-styrningen optimerar drivlinans konfiguration effektivt, med förberedelser för uppförsbacke eller nedförsbacke, så att batteriets SOC håller sig inom sina gränser och bränslecellen arbetar i mest optimala räckvidden. Detta säkerställer drift över olika typer av körcykler med den mest effektiva batteri- och bränslecellsstorleken, och avslutar därför med att MPC-styrenheten överträffar den regelbaserade.