This thesis stems from the interest of Holmen group to investigate the opportunitiesavailable for large electricity consumers in the Swedish primary reserve markets.The study performed focuses on one of Holmen's paper mill and it aims at identifyinga load inside the production process that is suitable for providing frequency containmentservices for the grid. The evaluation of the mill's consumption prole and the technicalrequirements of the reserve market led to the identication of the electric boiler coupledwith a steam accumulator as the most appropriate load.Five case study simulating the participation of the mill to dierent energy and reservemarkets have been evaluated. For each case a linear optimization problem has beenformulated. The rst simulation represents the current practice of the mill in relation tothe energy purchased on the spot market (following it will be also referred as referencecase). The second case study (II c.s.) integrates the use of the steam accumulator asa tool to perform thermal load shifting. In the third case study (III c.s.) the mill ismodelled to bid on the spot and primary reserve market by oering some capacity ofthe electric boiler. The last two case studies (IV and V c.s.) recalls the rst and lastpreviously mentioned, but also include the possibility of having energy imbalance. Thismeans that the imbalance settlement operated by eSett will produce an additional costor prot for the mill.The last three problem formulations fall under the denition of stochastic problems,since two random variable are present, namely: average hourly frequency value andimbalance settlement price. The uncertainty of the variables is represented throughscenarios.The outcome derived from the combination of the results for the winter and summercases shows that each strategy brings an economic saving when compared to the referencecase (I c.s.). The less interesting strategies are the ones that do not involve the reservemarket, leading to about 0.03% (II c.s.) and 0.06% (IV c.s.) of saving on the overallyearly energy cost. Contrariwise, by oering FCR-N capacity, the cost of electricitycan be cut by 5.15% (III c.s.) and 6.69% (V c.s.), respectively considering and notconsidering the imbalance settlement. / Avhandlingen har sitt ursprung i skogsindustrikoncernen Holmens intresse att undersökamöjligheten för stora elförbrukare att delta på den svenska primär-reservmarknaden. Studien som utförts fokuserar på ett av Holmens pappersbruk och syftar till att identifiera en elektrisk process som, inom bruksgränserna, är lämplig för att tillhandahålla frekvensregleringstjänster till det nationella nätet. En utvärdering av brukets elförbrukning samt de tekniska krav som ställs på reservmarknaden ledde till att en elektrisk panna med tillkopplad ångackumulator identifierades som mest lämplig.Fem budstrategier som simulerar brukets deltagande till olika energioch reservmarknader har presenterats. För varje strategi är ett linjärt optimeringsproblem formulerat. Den första strategin visar på nuvarande sätt bruket köper elektricitet på spotmarknaden. Den andra strategin integrerar användning av ångackumulatorn som ett verktyg för att utföra termisk lastskiftning. I den tredje modelleras deltagande också på primärreservmarknaden genom att erbjuda en viss kapacitet hos elpannan. De två sista strategierna baseras på den första och tredje, men tillåter i tillägg obalanser vilket innebär en extra kostnad eller möjlig intjäning för bruket.De tre sista problemformuleringarna faller under definitionen stokastiska problem, eftersom två slumpmässiga variabler är närvarande, nämligen: genomsnittligt timfrekvensvärde och priset för obalans. Osäkerheten för variablerna representeras genom scenarier.Resultatet visar att varje strategi ger en ekonomisk besparing jämfört med refer-ensfallet (strategi ett). De mindre intressanta strategierna är de som inte involverarreservmarknaden, vilka endast leder till ca 0,03% och 0,06% minskning av den totalaårliga energikostnaden. Däremot, genom att erbjuda FCR-N-kapacitet kan kostnaden för el minskas med 6,69% och 5,15% beroende s eller ej.

L’intégration croissante de la production éolienne ne participant pas au réglage de fréquence induit de nouvelles difficultés de gestion des systèmes électriques. Ces problèmes sont d’autant plus significatifs que le réseau est faible. La présente thèse vise à évaluer la performance et la fiabilité du réglage de fréquence des éoliennes à l’échelle du système électrique. Les études sont appliquées sur un réseau insulaire.D’abord, l’impact d’un fort taux de pénétration de la production éolienne sur l’allocation de la réserve primaire et sur le comportement dynamique du réseau est caractérisé. Il est montré que la participation des éoliennes au réglage de fréquence est techniquement indispensable pour le maintien de la sûreté du système électrique à partir d’un certain taux de pénétration. Deux solutions permettant aux éoliennes de contribuer au réglage de fréquence sont ensuite étudiées par simulations dynamiques. La performance d’une inertie émulée est caractérisée en considérant l’impact du point de fonctionnement initial des éoliennes et des paramètres du contrôleur. La contribution de la réserve éolienne à l’amélioration de la performance dynamique du système est également identifiée.Afin d’évaluer le potentiel et la fiabilité de la réserve éolienne, la dernière partie de ce travail est consacrée aux études statistiques prenant en compte la variabilité et l’incertitude de la prévision de la production. Deux stratégies du placement de réserve sont proposées et comparées. L’impact des erreurs de prévision sur le potentiel de réserve éolienne est également mis en évidence. Enfin l’énergie réglante d’une ferme et la plage de réglage du statisme éolien sont caractérisées / The increasing development of wind power that does not participate in frequency control leads to new challenges in the management of electrical power systems. The problems are more significant in weak power grids. The present thesis aims to evaluate the performance and the reliability of frequency response from wind turbines on a system-wide scale. Studies are applied onto an isolated power grid.First of all, the impact of high levels of wind penetration on primary reserve allocation and on grid dynamic behaviour is characterized. It is shown that the participation of wind turbines in frequency regulation is technically required for maintaining power system security from a certain wind penetration rate.Two solutions allowing wind turbines to contribute to frequency control are then studied through dynamic simulations. The performance of emulated inertia is characterized by taking into account the impact of initial wind operating point and controller parameters. The contribution of wind power reserve to system dynamic performance improvement is also identified.In order to assess the potential and the reliability of wind primary reserve, the last part of this research work is devoted to statistical analyses considering the variability and the prediction uncertainty of wind generation. Two strategies for reserve allocation are proposed and compared. The impact of forecast errors on the potential of wind power reserve is also highlighted. Finally the power frequency characteristic of a wind farm as well as the droop adjustment range is characterized

[pt] A crescente demanda de energia elétrica faz com que a complexidade dos sistemas elétricos de potência seja cada vez maior, associado às limitações na expansão do sistema de transmissão, resulta na operação dos sistemas elétricos mais próximos de seus limites, tornando-os vulneráveis a problemas de estabilidade de tensão. Nesse contexto, faz-se necessário o desenvolvimento de ferramentas computacionais capazes de representar os sistemas elétricos mais adequadamente, melhorando assim as condições de análise. Neste trabalho são apresentadas três modelagens do fluxo de carga mais completas que a modelagem clássica, a saber: a modelagem de múltiplas barras swing, a modelagem com regulação primária e a modelagem com parâmetros da rede de transmissão variáveis com a frequência. Uma vez utilizadas na solução do problema do fluxo de carga estas modelagens são estendidas para a realização do cálculo dos índices de estabilidade de tensão das barras de carga, barras de tensão controlada e barras swing. Testes numéricos com um sistema-teste de 6 barras são apresentados para a verificação da aplicabilidade e adequação dos modelos analisados. / [en] The growing demand for electricity increases the complexity of electric power systems which, when combined with limitations in the expansion of transmission systems, results in the operation of electrical systems closer to their limits, making them vulnerable to voltage stability problems. In this context, there is a gap in the market for the development of computational tools that can represent the electrical systems more appropriately, thereby improving the conditions of analysis. The present study formulates three non-classical load flow representations: multiple swing buses, primary frequency control, and frequency dependent transmission network parameters. Once used in the load flow problem solving, these models are also extended to allow the calculation of voltage stability indices of load buses, controlled voltage buses and swing buses. Numerical tests with a 6-bus test system are presented to verify the applicability and adequacy of the proposed models.

[pt] Cada dia a operação dos sistemas elétricos de energia é mais complexo. Mantiver um correto fornecimento da energia de forma empírica é uma tarefa difícil e pouco confiável, este trabalho se realizou para ajudar a atender com maior confiabilidade este fornecimento de energia. Neste trabalho apresentam-se modelagens de fluxo de carga para obter diferentes pontos de operação. Modelou-se a regulação própria da carga e o controle carga-frequência das unidades geradoras, incluindo regulação primária e secundária. As modelagens são estendidas para a avaliação da estabilidade de tensão, inclusive considerando-se a influência da frequência. A avaliação foi feita em pontos de operação antes e após a atuação do controle carga-frequência. Em cada caso, as variações de carga ou geração das barras em análise (infinitesimais) são absorvidas pelos geradores de diferentes formas: de acordo com os fatores de proporcionalidade na regulação secundária, com as energias de regulação na regulação primária ou com a proporcionalidade das gerações das barras swing no despacho proporcional. De acordo com o apresentado neste trabalho obtêm-se pontos de operação em regime permanente, nestes pontos de operação foi onde se realizo o cálculo da estabilidade de tensão para todas as barras do sistema. Os sistemas testados tiveram 6 e 39 barras. / [en] Each day the operation of electric power system is more complex. Maintain a correct supply of energy empirically is difficult and unreliable task, this work was realized to comply with more reliably this power supply. This dissertation presents the modeling of power flow to get different steady state. The load response to frequency deviation, the primary and the secondary frequency control were models. The models are extended to the evaluation of voltage stability, even considering the frequency influence. The evaluation is done in the state before and after the response of load-frequency control. In each case, the generators units absorb the variation (infinitesimal) in the load or in the generation (bus in analysis) in different ways: according to the proportionality factor in the secondary control, the speed regulations in the primary control or the proportionality of the swing bus generation in the proportional dispatch. According to the presented in this dissertation was obtained a state in permanent regime, in this state was evaluated the voltage stability in all bus of the system. The tested system had 6 and 39 bus.

The number of plug-in electric vehicles (PEVs) is likely to increase in the near future and these vehicles will probably be connected to the electric grid most of the day time. PEVs are interesting options to provide a wide variety of services such as primary frequency control (PFC), because they are able to quickly control their active power using electronic power converters. However, to evaluate the impact of PEVs on PFC, one should either carry out complex and time consuming simulation involving a large number of PEVs or formulate and develop aggregate models which could efficiently reduce simulation complexity and time while maintaining accuracy. This thesis proposes aggregate models of PEVs for PFC. The final aggregate model has been developed gradually through the following steps. First of all, an aggregate model of PEVs for the PFC has been developed where various technical characteristics of PEVs such as operating modes (i.e., idle, disconnected, and charging) and PEV’s state of charge have been formulated and incorporated. Secondly, some technical characteristics of distribution networks have been added to the previous aggregate model of PEVs for the PFC. For this purpose, the power consumed in the network during PFC as well as the maximum allowed current of the lines and transformers have been taken into account. Thirdly, the frequency stability margins of power systems including PEVs have been evaluated and a strategy to design the frequency-droop controller of PEVs for PFC has been described. The controller designed guaranties similar stability margins, in the worst case scenario, to those of the system without PEVs. Finally, a method to evaluate the positive economic impact of PEVs participation in PFC has been proposed. / En el futuro cercano se espera un notable incremento en el número de vehículos eléctricos enchufables (PEVs), los cuales están conectados a la red eléctrica durante la mayor parte del día. Los PEVs constituyen una opción interesante a la hora de proporcionar una amplia variedad de servicios, tales como el control primario de frecuencia (PFC), dado que tienen la capacidad de controlar rápidamente el flujo de potencia activa a través de convertidores electrónicos de potencia. Sin embargo, para evaluar el impacto de los PEVs sobre el PFC se debe llevar a cabo una simulación computacionalmente compleja y con un largo tiempo de simulación en la que se considere un gran número de PEVs. Otra opción sería la formulación y desarrollo de modelos agregados, los cuales podrían reducer eficazmente la complejidad y tiempo de simulación manteniendo una alta precisión. Esta tesis propone modelos agregados de PEVs para PFC. El modelo agregado definitivo ha sido desarrollado de manera gradual a través de los siguientes pasos. En primer lugar, se ha desarrollado un modelo agregado de PEVs para PFC en el cual son incorporadas varias características técnicas de los PEVs, tales como los modos de operación (inactivo, desconectado y cargando), y la formulación del estado de carga de los PEVs. En segundo lugar, ciertas características técnicas de las redes de distribución han sido consideradas en el modelo agregado de PEVs para PFC previamente propuesto. Para este fin, la potencia consumida por la red durante el PFC, así como la corriente máxima permitida en las líneas y transformadores han sido consideradas. En tercer lugar, se han evaluado los márgenes de estabilidad en la frecuencia de los sistemas de potencia que incluyen PEVs y se ha descrito una estrategia para diseñar un control de frecuencia-droop de PEVs para PFC. El controlador diseñado garantiza márgenes de estabilidad similares, en el peor de los casos, a aquellos de un sistema sin PEVs. Finalmente, se ha propuesto un método para evaluar el impacto económico positivo de la participación de los PEVs en el PFC. / Inom en snar framtid förväntas antalet laddbara bilar (laddbilar) öka kraftig, vilka tidvis kommer att vara anslutna till elnätet. Då laddbilar snabbt kan styra och variera sin aktiva laddningseffekt med hjälp av kraftelektroniken i omriktaren kan dessa fordon erbjuda en rad systemtjänster, såsom primär frekvensregleringen. Att utvärdera hur laddbilarna kan påverka den primära frekvensreglering är utmanande då en stor mängd laddbilar måste beaktas vilket kräver komplexa och tidskrävande simuleringar. Ett effektivt sätt att minska komplexiteten men bibehålla noggrannheten är genom att utforma och använda aggregerade modeller. Syftet med denna avhandling är att ta fram aggregerade modeller för laddbilars påverkan på primär frekvensreglering. Modellen har gradvis utvecklats genom följande steg. I första steget har en aggregerad modell av hur laddbilar kan användas för primär frekvensreglering utvecklats där olika tekniska detaljer så som laddbilars tillstånd (d.v.s. inkopplade, urkopplade eller laddas) och laddningnivån beaktats. I andra steget har en modell av distributionsnätet integrerats i den aggregerade modellen. Här tas hänsyn till effektflöden i elnätet samt begränsningar i överföringskapacitet i transformatorer och ledningar i distributionsnätet. I ett tredje steg har frekvensstabiliteten i ett elnät med laddbilar utvärderats och en strategi för hur en frekvensregulator kan designas för att tillhandahålla primär frekvensreglering med hjälp av laddbilar har utvecklats. Designen garanterar samma stabilitetsmarginal för styrsystemet både med och utan laddbilar. Dessutom föreslås en metod för att utvärdera de ekonomiska effekterna av att använda laddbilar för primär frekvensreglering. / Het aantal elektrische voertuigen (EV’s) zal zeer waarschijnlijk toenemen in de nabije toekomst en deze voertuigen zullen vermoedelijk gedurende het grootste deel van de dag aan het elektriciteitsnetwerk aangesloten zijn. EV’s zijn interessante opties om een grote verscheidenheid van diensten te leveren, zoals bijvoorbeeld primaire frequentieregeling, omdat ze snel hun actieve vermogen kunnen aanpassen met behulp van elektronische vermogensomvormers. Echter, om de invloed van EV’s en primaire frequentieregeling te kunnen evalueren, moet men complexe en tijdrovende simulaties met een groot aantal EVs uitvoeren of verzamelmodellen formuleren en ontwikkelen die de complexiteit en duur van de simulaties kunnen reduceren zonder nauwkeurigheid te verliezen. Dit onderzoek presenteert verzamelmodellen voor EV’s en primaire frequentieregeling. Het uiteindelijke verzamelmodel is geleidelijk ontwikkeld door de volgende stappen te nemen. Ten eerste is een verzamelmodel voor EV’s en primaire frequentieregeling ontwikkeld waar verscheidene technische karakteristieken van EV’s, zoals bedieningsmodi (bijv. Inactief, losgekoppeld en ladend) en de actuele laadtoestand in zijn geformuleerd en geïntegreerd. Ten tweede zijn enkele technische karakteristieken van distributienetwerken toegevoegd aan het eerdere verzamelmodel van EV’s voor primaire frequentieregeling. Hiervoor zijn de vermogensconsumptie in het network gedurende primaire frequentieregeling en de maximaal toegestane stroomsterkte van de kabels meegerekend. Ten derde zijn de marges voor de frequentiestabiliteit van elektriciteitssystemen met EV’s geëvalueerd en is een strategie voor het ontwerpen van de frequentie-droop regeling van de EV’s voor primaire frequentieregeling beschreven. De ontworpen controller garandeert soortgelijke stabiliteitsmarges in het slechtste scenario, als voor het systeem zonder EV’s. Ten slotte is er een methode voorgesteld om de positieve economische invloed van EV-participatie in primaire frequentieregeling te evaluëren. / <p>“SETS Joint Doctorate Programme</p><p>The Erasmus Mundus Joint Doctorate in Sustainable Energy Technologies and Strategies (SETS), the SETS Joint Doctorate, is an international programme run by six institutions in cooperation:</p><p>• Comillas Pontifical University, Madrid, Spain</p><p>• Delft University of Technology, Delft, the Netherlands</p><p>• Florence School of Regulation, Florence, Italy</p><p>• Johns Hopkins University, Baltimore, USA</p><p>• KTH Royal Institute of Technology, Stockholm, Sweden</p><p>• University Paris-Sud 11, Paris, France</p><p>The Doctoral Degrees provided upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology, and KTH Royal Institute of Technology.</p><p>The Degree Certificates are giving reference to the joint programme. The doctoral candidates are jointly supervised, and must pass a joint examination procedure set up by the three institutions issuing the degrees.</p><p>This Thesis is a part of the examination for the doctoral degree.</p><p>The invested degrees are official in Spain, the Netherlands and Sweden respectively.</p><p>SETS Joint Doctorate was awarded the Erasmus Mundus excellence label by the European Commission in year 2010, and the European Commission’s Education, Audiovisual and Culture Executive Agency, EACEA, has supported the funding of this programme</p><p>The EACEA is not to be held responsible for contents of the Thesis.”  QC 20170412</p>