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The following master thesis is conducted on behalf of The Royal Institute of Technology and Manetos AB with the purpose of investigating potential business markets for the new innovation, the Digital Circuit Breaker (DCB). The DCB is a mean for digitalising the distribution board, which is the middleman between households’ electrical appliances and the electrical grid. Through this digitalisation, a two-way communication between households and the grid can emerge, creating possibilities for demand side flexibility and energy management. The technology also provides more transparency for homeowners and real estate owners into households’ and buildings’ energy consumption, through monitoring and disaggregation. The study found that the energy landscape is facing significant challenges for the future. The integration of more intermittent energy, unpredictable energy consumption, new power consuming technologies and an aging grid were examples of challenges which potentially could jeopardize the security of electric supply. Many of these challenges however were also found to be issues which the DCB could potentially solve. It was also found that power-based tariffs spoke in favour of the DCB. Based on the overall empirical results, the study found that there is a need amongst utilities for demand side flexibility solutions and that there is a need amongst homeowners for electricity transparency and monitoring tools. This gives rise to a situation where the possibility to commercialize the DCB exists. By making the DCB a demand flexibility solution for utilities and a transparency and monitoring tool for homeowners, the needs for both utilities and homeowners can be fulfilled. The recommendations towards Manetos were to focus on the business markets electric utilities, more specifically municipally owned grid companies, and homeowners. It was found that the municipally owned grid companies focused more on socioeconomics than profit based grid companies. Furthermore, the municipally owned grid companies that had powerbased tariffs in place today showed great interest in the DCB as a tool for better managing electrical load and avoiding power peaks. For homeowners it was found that the people who owned electric vehicles or had direct electric heating showed great interest in an electricity management tool such as the DCB. The study also found real estate companies to be a business market of interest, however, not enough interviews were conducted in order to draw conclusions for the markets viability. Therefore, further investigation of the real estate company market is recommended. / Följande examensarbete har utförts på uppdrag av Kungliga Tekniska Högskolan och Manetos AB med syftet att undersöka potentiella affärsmarknader för en ny innovation kallad den Digitala Brytaren (DCB – Digital Circuit Breaker). DCBn är ett verktyg för att digitalisera elskåpet, vilket fungerar som en mellanhand mellan hushåll och elnätet. Denna digitalisering möjliggör för tvåvägskommunikation mellan hushåll och elnät, vilket öppnar upp möjligheter för efterfrågeflexibilitet och bättre energihushållning. Teknologin ökar även transparensen gällande byggnaders energikonsumtion, både för hushåll och fastighetsägare, genom övervakning och dissaggregering. Studien fann att energilandskapet står inför betydande utmaningar inför framtiden. Integrationen av mer intermittent energi, oförutsägbar energikonsumtion, nya teknologier och ett åldrande elnät är några exempel på utmaningar vilka kan komma att äventyra leveranssäkerheten i systemet. Många av dessa utmaningar visade sig dock vara problem som DCBn skulle kunna lösa. Studien fann även att effektbaserade tariffer, vilka idag används som ett verktyg för att motverka höga effektuttag, fungerar som incitament för DCBn och för en mer hållbar energikonsumtion generellt. Baserat på de övergripande empiriska resultaten fann studien att det finns ett behov för efterfrågeflexibilitets lösningar bland elnätsägare, samt ett behov för transparens- och kontroll-verktyg för villaägare. Detta ger möjlighet för att kommersialisera DCBn. Behoven hos både elnätsägare och villaägare kan uppnås genom att paketera DCBn som ett efterfrågeflexibilitets-, transparens- och övervaknings-verktyg. Rekommendationen till Manetos var att fokusera på kundsegmenten elnätsägare, främst de kommunalt ägda, samt villaägare. Studien fann att kommunalägda elnätsägare fokuserade mer på samhällsekonomi är de vinstdrivande elnätsföretagen. Vidare så fann studien att de kommunala elnätsägarna vilka idag använder effekt tariffer, hade ett stort intresse för DCBn som ett verktyg för att minska effekttoppar och uppnå bättre övervakning. För villaägare kunde det ses att de personer som ägde elbilar eller hade direktverkande el i bostaden visade störst intresse för ett verktyg såsom DCBn. Även kundsegmentet fastighetsägare visade sig vara av intresse, dock genomfördes inte ett tillräckligt stort antal intervjuer inom segmentet för att kunna dra slutsatser om marknadens lönsamhet. Därför föreslås undersökning av detta segment för vidare framtida studier, såväl som att undersöka potentialen för DCBn internationellt samt att inkludera ett större antal villaägare i studien.

Electric power systems continue to increase in complexity because of the deployment of market mechanisms, the integration of renewable generation and distributed energy resources (DER) (e.g., wind and solar), the penetration of electric vehicles and other price sensitive loads. These revolutionary changes and the consequent increase in uncertainty and dynamicity call for significant modifications to power system operation models including unit commitment (UC), economic load dispatch (ELD) and optimal power flow (OPF). Planning and operation of these ???smart??? electric grids are expected to be impacted significantly, because of the intermittent nature of various supply and demand resources that have penetrated into the system with the recent advances. The main focus of this thesis is on the application of the Affine Arithmetic (AA) method to power system operational problems. The AA method is a very efficient and accurate tool to incorporate uncertainties, as it takes into account all the information amongst dependent variables, by considering their correlations, and hence provides less conservative bounds compared to the Interval Arithmetic (IA) method. Moreover, the AA method does not require assumptions to approximate the probability distribution function (pdf) of random variables. In order to take advantage of the AA method in power flow analysis problems, first a novel formulation of the power flow problem within an optimization framework that includes complementarity constraints is proposed. The power flow problem is formulated as a mixed complementarity problem (MCP), which can take advantage of robust and efficient state-of-the-art nonlinear programming (NLP) and complementarity problems solvers. Based on the proposed MCP formulation, it is formally demonstrated that the Newton-Raphson (NR) solution of the power flow problem is essentially a step of the traditional General Reduced Gradient (GRG) algorithm. The solution of the proposed MCP model is compared with the commonly used NR method using a variety of small-, medium-, and large-sized systems in order to examine the flexibility and robustness of this approach. The MCP-based approach is then used in a power flow problem under uncertainties, in order to obtain the operational ranges for the variables based on the AA method considering active and reactive power demand uncertainties. The proposed approach does not rely on the pdf of the uncertain variables and is therefore shown to be more efficient than the traditional solution methodologies, such as Monte Carlo Simulation (MCS). Also, because of the characteristics of the MCP-based method, the resulting bounds take into consideration the limits of real and reactive power generation. The thesis furthermore proposes a novel AA-based method to solve the OPF problem with uncertain generation sources and hence determine the operating margins of the thermal generators in systems under these conditions. In the AA-based OPF problem, all the state and control variables are treated in affine form, comprising a center value and the corresponding noise magnitudes, to represent forecast, model error, and other sources of uncertainty without the need to assume a pdf. The AA-based approach is benchmarked against the MCS-based intervals, and is shown to obtain bounds close to the ones obtained using the MCS method, although they are slightly more conservative. Furthermore, the proposed algorithm to solve the AA-based OPF problem is shown to be efficient as it does not need the pdf approximations of the random variables and does not rely on iterations to converge to a solution. The applicability of the suggested approach is tested on a large real European power system.

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[pt] O aumento significativo de pequenas usinas de geração, impulsionado pela privatização do mercado de oferta de energia elétrica e avanços tecnológicos, apresenta desafios no acesso desses empreendimentos ao sistema de transmissão. Em algumas regiões, o aumento da implantação de usinas cria filas para acesso à rede elétrica, potencialmente resultando em uma escassez de margem de transmissão. Isso é caracterizado pela saturação de escoamento de potência em áreas geográficas com elevado potencial para fontes renováveis (como eólica e solar), impactando negativamente o planejamento e operação do sistema de transmissão. Esta Dissertação de Mestrado propõe uma abordagem de avaliação probabilística dos riscos associados à entrada de novos geradores, com destaque para fontes eólicas e fotovoltaicas. A utilização do fluxo de potência probabilístico, por meio da simulação de Monte Carlo, estende as capacidades do método determinístico, proporcionando uma melhor representação da intermitência inerente das fontes renováveis variáveis e possíveis contingências de equipamentos. Os estudos realizados no sistema teste IEEE RTS 79 - 24 barras, considerando a incorporação de usinas renováveis, permitem compreender a importância do método probabilístico no fornecimento de informações mais representativas aos tomadores de decisão. A proposta de reformulação do processo de acesso, adaptando métodos de cálculo para refletir a complexidade do cenário atual de geração de energia, emerge como um caminho promissor à utilização eficiente do sistema de transmissão, especialmente diante da crescente presença de fontes renováveis. / [en] The significant increase in small generation plants, driven by the privatization of the electricity supply market and technological advances, presents challenges in terms of their access to the transmission system. In some regions, the increasing deployment of power plants creates queues for access to the grid, potentially resulting in a transmission margin shortage. This is characterized by the saturation of power flow in geographical areas with high potential for renewable sources (such as wind and solar), negatively impacting the planning and operation of the transmission system. This Master s Thesis proposes a probabilistic approach to assessing the risks associated with the entry of new generators, especially wind and photovoltaic sources. The use of probabilistic power flow, through Monte Carlo simulation, extends the capabilities of the deterministic method, providing a better representation of the inherent intermittency of variable renewable sources and possible equipment contingencies. The studies carried out on the IEEE RTS 79 - 24-bus test system, considering the incorporation of renewable power plants, allow us to understand the importance of the probabilistic method in providing decision-makers with more representative information. The proposal to reformulate the access process, adapting calculation methods to reflect the complexity of the current energy generation scenario, emerges as a promising way of making efficient use of the transmission system, especially given the growing presence of renewable sources.

In an electrical system there needs to be a constant balance between supply and demand ofelectricity and this is measured by the frequency in the grid. Due to the increasing awarenessof climate change, more renewable energy resources have been introduced in the Swedishelectricity system. This is, however, not solely positive since renewable energy sources areoften of intermittent character which entails more imbalances between supply and demand. Inaddition, statistics and data show that the deviation in the frequency in the Nordic system hasincreased during the latest years. Thus, in this thesis, the issues regarding the frequency havebeen addressed by examining the demand for frequency control in the Swedish electricitysystem and what balancing efforts that can be carried out on a local level to contribute to abetter balanced system. This thesis has been conducted at KTH Royal Institute of Technologywith collaboration with the commissioner Mälarenergi AB. A case study of the Swedish electricity system has been carried out to gather empiricalmaterial and this material has been analyzed using Geels theory on technical transitions, themulti-level perspective. The results indicates that it is likely the demand for frequency controlwill increase, and this is due to factors as more intermittent energy, current market design fortrading electricity, overseas transmission connections, decommissioning of nuclear powerand limited internal transmission capacity. Three other developments have been identified,which could have a large impact on the demand in the future, as an increasing use of electricvehicles, prosumers and the deployment of IoT in the energy sector. These developmentshave not been integrated to a large extent yet in the energy sector and thus have a moreuncertain impact. In terms of resources, the thesis has identified that it is likely that hydropower will continueto be the main resource for frequency regulation. Another source that could be used morefrequently than today and possibly compete with hydropower is combined heat and powerplants. Furthermore, the study has found that local actors can contribute by advertisingsmaller local resources on a market for trading regulating power called“reglerkraftmarknaden”, that balance providing companies collaborate, that the load iscontrolled in the local grids or that smaller local production facilities are operated in standalonemode during extreme situations. / För att uppnå ett välfungerande elektrisk system så måste det vara en konstant balans mellan produktion och konsumtion av el i systemet. Den här balansen mäts genom att mäta frekvensen i elnätet. Eftersom allt fler har blivit mer medvetna om de klimatförändringar vår planet står inför har det successivt införts mer och mer förnybara energikällor i det svenska elsystemet. Den här utvecklingen har inte enbart varit positivt, eftersom förnybara energikällor ofta är av intermittent karaktär, vilket har medfört att balansen mellan produktion och konsumtion av el har försämrats. Flertalet undersökningar har påvisat att det förekommer mer frekvensavvikelser i det nordiska elsystemet idag än tidigare. Denna rapport har således undersökt dessa problem genom att analysera efterfrågan på frekvensreglering i det svenska elsystemet och vilka initiativ som kan tas på lokal nivå för att förbättra balansen i elsystemet. Rapporten har genomförts på Kungliga Tekniska Högskolan i samarbete med uppdragsgivaren Mälarenergi AB. Rapporten har genomfört en fallstudie av det svenska elsystemet för att samla in empiriskt material, och detta material har i sin tur analyserats genom Geels flernivåsansats. De resultat som har framkommit i undersökningen visar på att det är troligt att efterfrågan av frekvensreglering kommer att öka. Denna ökning beror på faktorer som att mer intermittent energi integreras i elnätet, hur marknaden för att handla elektricitet är utformad, fler utländska överföringsförbindelser, nedrustning av kärnkraft och begränsad överföringskapacitet inom det nationella elnätet. Tre andra utvecklingar har identifierats som möjligen kan ha en stor påverkan på behovet av frekvensreglering. Dessa är ett ökat antal elektriska fordon, prosumenter och att energisektorn integreras av IoT och smarta objekt i större utsträckning än idag. Dessa faktorer har inte integrerats i det svenska elsystemet nämnvärt ännu och deras påverkan är därmed mer osäker. Denna studie har också kommit fram till att vattenkraft troligtvis kommer fortsätta att vara den resurs som används mest för frekvensreglering, men även att kraftvärmeverk har potential att användas mer för reglering än idag. Vidare har rapporten även identifierat att lokala aktörer kan bidra till en bättre balans i systemet genom att antingen annonsera mindre lokala resurser på reglerkraftmarknaden, öka samarbetet mellan balansansvariga företag, kontrollera lasten i lokala elnät eller att mindre lokala produktionsanläggningar drivs i ö-drift under extrema situationer.

[pt] A demanda global por soluções sustentáveis para geração de energia elétrica cresceu rapidamente nas últimas décadas, sendo impulsionada por incentivos fiscais dos governos e investimentos em pesquisa e desenvolvimento de tecnologias. Isso provocou uma crescente inserção de fontes renováveis nas redes elétricas ao redor do mundo, criando novos desafios críticos para as avaliações de desempenho dos sistemas que são potencializados pela intermitência desses recursos energéticos combinada às falhas dos equipamentos de rede. Motivado por esse cenário, esta dissertação aborda a estimativa de risco de inadequação de grandezas elétricas, como ocorrências de sobrecarga em ramos elétricos ou subtensão em barramentos, através do uso do fluxo de potência probabilístico, baseado na simulação Monte Carlo e no método de entropia cruzada. O objetivo é determinar o risco do sistema não atender a critérios operativos, de forma precisa e com eficiência computacional, considerando as incertezas de carga, geração e transmissão. O método é aplicado aos sistemas testes IEEE RTS 79 e IEEE 118 barras, considerando também versões modificadas com a inclusão de uma usina eólica, e os resultados são amplamente discutidos. / [en] The global demand for sustainable solutions for electricity generation has grown rapidly in recent decades, driven by government tax incentives and investments in technology research and development. This caused a growing insertion of renewable sources in power networks around the world, creating new critical challenges for systems performance assessments that are enhanced by the intermittency of these energy resources combined with the failures of network equipment. Motivated by this scenario, this dissertation addresses the estimation of risk of inadequacy of electrical quantities, such as overload occurrences in electrical branches or undervoltage in buses, through the use of probabilistic power flow, based on Monte Carlo simulation and the cross-entropy method. The objective is to determine the risk of the system not meeting operational criteria, precisely and with computational efficiency, considering load, generation and transmission uncertainties. The method is applied to IEEE RTS 79 and IEEE 118 bus test systems, also considering modified versions with the inclusion of a wind power plant, and the results are widely discussed.