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Energy efficiency and renewable energy become more attractive in smart grid. In order to efficiently reduce global energy usage in building energy systems and to improve local environmental sustainability, it is essential to optimize the operation and the performance of combined heat and power (CHP) systems. In addition, intermittent renewable energy and imprecisely predicted customer loads have introduced great challenges in energy-efficient buildings' optimal operation. In the deterministic optimal operation, we study the modeling of components in energy-efficient building systems, including the power grid interface, CHP and boiler units, energy storage devices, and building appliances. The mixed energy resources are applied to collaboratively supply both electric and thermal loads. The results show that CHP can effectively improve overall energy efficiency by coordinating electric and thermal power supplies. Through the coordinated operation of all power sources, the daily operation cost of building energy system for generating energy can be significantly reduced. In order to address the risk from energy consumption forecast errors and renewable energy production volatility, we utilize the approach of stochastic programming and robust optimizations to operate energy-efficient building systems under uncertainty. The multi-stage stochastic programming model is introduced so that the reliable operation of building energy systems would be probabilistically guaranteed with stochastic decisions. The simulation results show that the stochastic operation of building energy systems is a promising strategy to account for the impact of the uncertainty on power dispatch decisions of energy-efficient building systems. In order to provide absolute guarantee for the reliable operation of building energy systems, a robust energy supply to electric and thermal loads is studied by exploring the effectiveness of energy storage on energy supply against the uncertainty. The robustness can be adjusted to control the conservativeness of the proposed robust operation model. For the purpose of achieving adaptability in the robust optimal operation and attaining robustness in the stochastic optimal operation of building energy systems, we also develop an innovative robust stochastic optimization (RSO) model. The proposed RSO model not only overcomes the conservativeness in the robust operation model, but also circumvents the curse of dimensionality in the stochastic operation model.

Smart grid is a power supply system that uses digital communication technology to detect and react to local changes for power demand. Modern and future power supply system requires a distributed system for effective communication and management. Blockchain, a distributed technology, has been applied in many fields, e.g., cryptocurrency exchange, secure sharing of medical data, and personal identity security. Much research has been done on the application of blockchain to smart grid. While blockchain has many advantages, such as security and no interference from third parties, it also has inherent disadvantages, such as untrusted network environment, lacking data source privacy, and low network throughput.In this research, three systems are designed to tackle some of these problems in blockchain technology. In the first study, Information-Centric Blockchain Model, we focus on data privacy. In this model, the transactions created by nodes in the network are categorized into separate groups, such as billing transactions, power generation transactions, etc. In this model, all transactions are first encrypted by the corresponding pairs of asymmetric keys, which guarantees that only the intended receivers can see the data so that data confidentiality is preserved. Secondly, all transactions are sent on behalf of their groups, which hides the data sources to preserve the privacy. Our preliminary implementation verified the feasibility of the model, and our analysis demonstrates its effectiveness in securing data source privacy, increasing network throughput, and reducing storage usage. In the second study, we focus on increasing the network’s trustworthiness in an untrusted network environment. A reputation system is designed to evaluate all node’s behaviors. The reputation of a node is evaluated on its computing power, online time, defense ability, function, and service quality. The performance of a node will affect its reputation scores, and a node’s reputation scores will be used to assess its qualification, privileges, and job assignments. Our design is a relatively thorough, self-operated, and closed-loop system. Continuing evaluation of all node’s abilities and behaviors guarantees that only nodes with good scores are qualified to handle certain tasks. Thus, the reputation system helps enhance network security by preventing both internal and external attacks. Preliminary implementation and security analysis showed that the reputation model is feasible and enhances blockchain system’s security. In the third research, a countermeasure was designed for double spending. Double spending is one of the two most concerned security attacks in blockchain. In this study, one of the most reputable nodes was selected as detection node, which keeps checking for conflict transactions in two consecutive blocks. Upon a problematic transaction was discovered, two punishment transactions were created to punish the current attack behavior and to prevent it to happen in future. The experiment shows our design can detect the double spending effectively while using much less detection time and resources.

As distributed generation penetrates the electric power grid at higher power levels, grid interface issues with distributed generation must be addressed. The current power system consists of central power generators, while the future power system will include many more distributed resources. The centralized power generation system is controlled by utility operators, but many distributed resources will not be controlled by utility operators. Distributed generation must use smart control techniques for high reliability and ideal grid interface. This thesis discusses the grid interface issue of anti-islanding. An electric island occurs when a circuit breaker in the electric power system trips. The distributed resource should disconnect from the electric grid for safety reasons. This thesis will give an overview of the possible methods. Each method will be analyzed using the ability to detect under the non-detection zone and the economic feasibility of the method. This thesis proposes two addition cases for analysis that exist in the electric power system: the effect of multiple methods in parallel in the non-detection zone and the possibility of a false trip caused by a load step. Multiple methods in parallel are possible because the islanding detection method is patentable, so each grid interface inverter company is likely to implement a different islanding detection method. The load step represents a load change when a load is switched on. / Master of Science

Le réseau électrique a subi d’importantes évolutions ces dernières décennies, pour devenir ce qu’on appelle le Smart Grid. Le réseau électrique évolue actuellement d’une architecture centralisée vers une architecture décentralisée, tenant compte des consommations et sources d’énergies à caractère imprédictible et irrégulier. L’Advanced Metering Infrastructure est une architecture clé du Smart Grid qui permet des communications bidirectionnelles entre le consommateur et le fournisseur d’énergie. Les réseaux de compteurs intelligents qui constituent notamment cette architecture reposent communément sur des communications à courant porteur, une technologie qui est hautement sensible aux interférences. Malgré l’utilisation de protocoles de niveau 2 spécifiques, les technologies employées ne permettent pas de respecter les exigences de toutes les applications Smart grid. La plupart des technologies considérées pour les réseaux de compteurs intelligents sont de courte portée, chaque compteur ne peut communiquer directement avec le concentrateur. Les noeuds doivent collaborer entre eux, utilisant un protocole de routage tel que RPL pour atteindre la destination. Le but de cette thèse est d’adapter RPL à un environnement multi interfaces, et étudier comment l’hétérogénéité des interfaces peut améliorer la fiabilité et les performances d’un réseau de compteurs intelligents. / Since decades, the power grid is Under going a tremendous evolution, toward what is called the Smart Grid. The grid is actually evolving from a centralized architecture to a decentralized one, taking into account all the unpredictable sources and consumption. The Advanced Metering Infrastructure is the network dedicated to the Smart Grid that allows two-ways communications between the consumers and the energy providers. Smart Meters networks, that are part of this architecture, rely on powerline communications, a technology that is highly sensitive to interference. Despite dedicated layer 2 protocols, the employed technologies cannot fulfill most of smart grid applications requirements. The majority of smart meter network technology candidates are short range, each meter cannot reach the concentrator in one hop. Nodes need to collaborate, using a routing protocol like RPL to reach the destination. The goal of this thesis is to modify RPL to a multi interfaces environment, and study how interface heterogeneity could increase the reliability and the performance of a smart meter network.

Com o crescimento constante da infraestrutura do sistema de distribuição de baixa tensão, tem-se a necessidade de um monitoramento mais preciso das grandezas elétricas no ponto de conexão com os clientes. O impacto da implantação de sistemas smart grids são positivos, visto que para o lado do consumidor o acompanhamento do consumo de forma online permite realizar um melhor planejamento, e para o lado da concessionária, o levantamento de perfil dos clientes e planejamento de demanda, visto que os medidores podem fornecer os dados em tempo real de horários de maior consumo e acompanhamento dos níveis, de forma a adequar conforme os níveis de qualidade de energia definidos pelo módulo 8 PRODIST. Além do acompanhamento, das variáveis e limites, este projeto poderá atuar de forma a auxiliar as companhias elétricas a comparar os pontos de cargas estimadas com o fornecimento para detectar possíveis fraudes no ponto de distribuição. Outro aspecto importante é tornar possível a integração com uma rede de clientes que além de consumidores podem tornar-se pequenas unidades geradoras, alimentando o sistema maior. / With the constant growth of the infrastructure of the low voltage distribution system, there is a need for a more refined monitoring of the electrical quantities in the distribution network. The impact of the implementation of smart grids systems are positive, since for the consumer side the monitoring of consumption in an online way allows to carry out consumption planning, and for the side of the concessionaire, customer profile survey and demand planning, Since the meters can provide the real time data of schedules of greater consumption and monitoring of the levels, in order to adapt according to the levels of quality of energy defined by the module 8 PRODIST. In addition to the monitoring of variables and limits, this project may act in a way that helps utilities compare the estimated load points with the supply to detect possible fraud at the distribution point. Another important aspect is to make it possible to integrate with a network of customers that in addition to consumers can become small generating units, feeding the larger system.

Com o crescimento constante da infraestrutura do sistema de distribuição de baixa tensão, tem-se a necessidade de um monitoramento mais preciso das grandezas elétricas no ponto de conexão com os clientes. O impacto da implantação de sistemas smart grids são positivos, visto que para o lado do consumidor o acompanhamento do consumo de forma online permite realizar um melhor planejamento, e para o lado da concessionária, o levantamento de perfil dos clientes e planejamento de demanda, visto que os medidores podem fornecer os dados em tempo real de horários de maior consumo e acompanhamento dos níveis, de forma a adequar conforme os níveis de qualidade de energia definidos pelo módulo 8 PRODIST. Além do acompanhamento, das variáveis e limites, este projeto poderá atuar de forma a auxiliar as companhias elétricas a comparar os pontos de cargas estimadas com o fornecimento para detectar possíveis fraudes no ponto de distribuição. Outro aspecto importante é tornar possível a integração com uma rede de clientes que além de consumidores podem tornar-se pequenas unidades geradoras, alimentando o sistema maior. / With the constant growth of the infrastructure of the low voltage distribution system, there is a need for a more refined monitoring of the electrical quantities in the distribution network. The impact of the implementation of smart grids systems are positive, since for the consumer side the monitoring of consumption in an online way allows to carry out consumption planning, and for the side of the concessionaire, customer profile survey and demand planning, Since the meters can provide the real time data of schedules of greater consumption and monitoring of the levels, in order to adapt according to the levels of quality of energy defined by the module 8 PRODIST. In addition to the monitoring of variables and limits, this project may act in a way that helps utilities compare the estimated load points with the supply to detect possible fraud at the distribution point. Another important aspect is to make it possible to integrate with a network of customers that in addition to consumers can become small generating units, feeding the larger system.

L'arrivée des véhicules électriques (VEs) a un impact non négligeable sur le réseau électrique, à cause de la grande quantité d'énergie demandée. La stabilité du réseau est susceptible d'être menacée. Cependant, dans l'optique de la transition du réseau électrique vers le Smart Grid, les VEs peuvent aussi être vus comme offrant de nouvelles opportunités. Grâce à la flexibilité des VE demande, leur présence ouvre la voie à des optimisations via le processus de recharge ou même par l'utilisation de cette nouvelle capacité de stockage d'énergie distribuée. Dans cette thèse, nous nous intéressons aux aspects économiques liés à la VE recharge, en prenant en compte le fait que l'écosystème associé aux VEs implique un grand nombre d'acteurs divers, aux objectifs rarement alignés et chaque acteur peut prendre des décisions stratégiques. Je présente d'abord un état de l'art structuré des modèles de la littérature introduits pour ces problèmes. Nous décrivons et comparons les principales approches, en mettant en évidence les besoins en communication des mécanismes correspondants, et les principales propriétés économiques afin de souligner les résultats les plus significatifs ainsi que les éventuels manques. Nous faisons ensuite une proposition consistant à utiliser le processus de VE recharge pour fournir un service de régulation au réseau électrique, en adaptant la puissance instantanée de charge. Nous conduisons une analyse économique des incitations en jeu. En particulier, nous analysons les valeurs des incitations à la régulation qui sont suffisantes pour qu'une offre de recharge-régulation soit bénéfique à la fois pour l'agrégateur et le réseau. Cette étude étant initialement conduite dans le cas d'un monopole qui peut offrir une recharge normale ou une recharge-régulation. Nous regardons ensuite l'impact de la compétition, entre un agrégateur n'offrant que des recharges à puissance fixe, et un autre n'offrant que de la recharge-régulation. La compétition semble préférable pour les utilisateurs et pour la société, puisque les prix sont alors plus bas qu'avec le monopole, et que la participation aux services de régulation est bien plus élevée. Enfin, nous proposons d'utiliser une autre propriété des VEs, à savoir leur capacité de stockage d'énergie. En effet, les VEs peuvent se charger pendant les heures de faible demande, donc à des prix réduits, et éventuellement revendre une partie pendant les pics de demande. Nous menons une étude économique des gains et coûts d'une telle approche. A partir de valeurs réalistes des marchés de l'électricité, nous déterminons numériquement les conditions pour qu'un tel scénario soit viable, et quantifions les économies qu'il peut apporter. Cette dissertation se conclut par une prise de recul sur les contributions et sur les extensions qui pourraient y être apportées. / Electric Vehicles (EVs), as their penetration increases, are not only challenging the sustainability of the power grid, but also stimulating and promoting its upgrading. Indeed, EVs can actively reinforce the development of the Smart Grid if their charging processes are properly coordinated through two-way communications, possibly benefiting all types of actors. Because grid systems involve a large number of actors with nonaligned objectives, we focus on the economic and incentive aspects, where each actor behaves in its own interest. We indeed believe that the market structure will directly impact the actors' behaviors, and as a result the total benefits that the presence of EVs can earn the society, hence the need for a careful design. The thesis first provides an overview of economic models considering unidirectional energy flows, but also bidirectional energy flows, i.e., with EVs temporarily providing energy to the grid. We describe and compare the main approaches, summarize the requirements on the supporting communication systems, and propose a classification to highlight the most important results and lacks. We propose to use the recharging processes of EVs to provide regulation to the grid by varying the instantaneous recharging power. We provide an economic analysis of the incentives at play, including the EV owners point of view (longer recharging durations and impact on battery lifetime versus cheaper energy) and the aggregator point of view (revenues from recharging versus regulation gains). In particular, we analyze the range of regulation rewards such that offering a regulation-oriented recharging benefits both EV owners and the aggregator. After that, we split the monopolistic aggregator into two competing entities. We model a non-cooperative game between them and examine the outcomes at the Nash equilibrium, in terms of user welfare, station revenue and electricity prices. As expected, competing stations offer users with lower prices than the monopolistic revenue-maximizing aggregator do. Furthermore, the amount of regulation service increases significantly than that in the monopolistic case. Considering the possibility of discharging, we propose an approach close to Vehicle-to-Grid, where EVs can give back some energy from their batteries during peak times. But we also use EVs as energy transporters, by taking their energy where it is consumed. A typical example is a shopping mall with energy needs, benefiting from customers coming and going to alleviate its grid-based consumption, while EV owners make profits by reselling energy bought at off-peak periods. Based on a simple model for EV mobility, energy storage, and electricity pricing, we quantify the reduction in energy costs for the EV-supported system, and investigate the conditions for this scenario to be viable.

Les systèmes technologiques actuels comprennent une composante sociétale due àl’impact des utilisateurs. Ces systèmes, dits complexes, comportent des sous-systèmesdont les acteurs ont des objectifs divergents voire antagoniques.Considéré comme une évolution du réseau énergétique actuel, le Smart Grid est unparfait exemple de système complexe. Ce terme désigne en particulier un réseau électriqueoptimisé intégrant le comportement et les actions des utilisateurs (producteurs,consommateurs, consommacteurs, etc.). L’étude de la dynamique du système a pourobjectif d’améliorer sa qualité et sa sécurité et de réduire son impact environnemental.Cependant, les simulations de Smart Grid actuelles sont généralement basées sur destechnologies spécifiques, limitant l’évolution du modèle proposé.Les défis liés au Smart Grid sont l’hétérogénéité des actions et de leurs intérêts divergeant,et une complexité à toute échelle, que ce soit spatiale ou temporelle. En effet, lesentités du Smart Grid sont en compétition pour l’obtention de la ressource commune.Par exemple, les consommateurs ont des besoins énergétiques à un cout minimal tandisque les producteurs doivent contrôler la consommation, les pics de demande tout enmaximisant leur profit. Les comportements et les relations entre les entités sont doncdifficiles à modéliser. Des pressions externes et internes comme la dynamique des prix oules productions erratiques des énergies renouvelables ont une influence sur la structure,l’organisation et le comportement des sous-systèmes et donc du système global. De plus,une mauvaise gestion peut provoquer de nombreuses défaillances du système telles quedes brownouts, des blackouts ou des ruptures de lignes du réseau.Nous proposons une modélisation intégrative pour aborder le concept de Smart Grid :chaque composante de notre modélisation prend en compte un aspect de ce dernier et leurintrication mène à une modélisation efficace à toute échelle. Les relations entre entitésprennent en compte le caractère dynamique et un superviseur global surveille le réseaupour détecter les seuils critiques ou pour planifier les schémas de consommation future.Cependant, le modèle est impossible à appréhender tel quel et de nombreux scénariostesteront l’influence des divers paramètres, calibreront les algorithmes et ajusteront lagestion locale et globale pour une configuration donnée. Nous proposerons de nouvellesthéories pour améliorer ce modèle au niveau de la structure, de la dynamique des prixou une approche mathématique dans le but de rendre le modèle le plus efficace possible / Current technological systems include a societal component due to the impact of users.These complex systems contain numerous sub-systems which actors have conflicting evenantagonist objectives.Considered as the evolution of the current Power Grid, the Smart Grid is a perfectexample of complex system. This term refers to an electrical optimized network integratingthe behavior and actions of users (generators, consumers, consumactors, etc.).These Power Grid’s upgrades aim to improve quality and security, to reduce environmentalimpact. But current simulations are done on a specific technology and with alimited evolution.Challenges of Smart Grid are related firstly to the heterogeneity of actors with differentinterests and secondly to a spatial and temporal multiscale complexity. Smart Gridactors are in a competitive access to a shared resource. For example, consumers expressenergy requirements with minimal cost while producers have to manage consumption,peaks and to maximize their profits. Dynamics behaviors and relations between entitiesare difficult to model. External and internal pressures as energy pricing, energy losses orthe erratic production of renewable energies influence on the structure, the organizationand the behavior of the subsystems and the overall system. Moreover, a bad managementcauses various structural problems like brownout, blackout, or partial failures.We propose an integrative model to solve the Smart Grid: each component of ourmodel allows to consider one aspect of the grid and it is their intricacy that achieves anefficient modeling. Relations between entities take into account the complex dynamicsand an overall supervisor allows network monitoring to detect critical thresholds or toplan consumption schemes. However, the model is impossible to apprehend like this anddifferent scenarios test the influence of parameters, calibrate algorithms and adjust globaland local monitoring for a specific case. We also propose some theories to enhance thestructural model, to integrate dynamic pricing or to help to calibrate by a mathematicalapproach of the global problem

Dans le contexte de transition vers un système électrique décentralisé et intelligent, nous abordons le problème de la gestion des flexibilités de consommation électriques. Nous développons différentes méthodes basées sur l'optimisation distribuée et la théorie des jeux.Nous commençons par adopter le point de vue d'un opérateur central en charge de la gestion des flexibilités de plusieurs agents. Nous présentons un algorithme distribué permettant le calcul des profils de consommations des agents optimaux pour l'opérateur.Cet algorithme garantit la confidentialité des agents~: les contraintes individuelles, ainsi que le profil individuel de consommation de chaque agent, ne sont jamais révélés à l'opérateur ni aux autres agents.Ensuite, nous adoptons dans un second modèle une vision plus décentralisée et considérons un cadre de théorie des jeux pour la gestion des flexibilités de consommation.Cette approche nous permet en particulier de modéliser les comportements stratégiques des consommateurs.Dans ce cadre, une classe de jeux adéquate est donnée par les jeux de congestion atomiques fractionnables.Nous obtenons plusieurs résultats théoriques concernant les équilibres de Nash dans cette classe de jeux, et nous quantifions l'efficacité de ces équilibres en établissant des bornes supérieures sur le prix de l'anarchie.Nous traitons la question du calcul décentralisé des équilibres de Nash dans ce contexte en étudiant les conditions et les vitesses de convergence des algorithmes de meilleure réponse et de gradient projeté.En pratique un opérateur peut faire face à un très grand nombre de joueurs, et calculer les équilibres d'un jeu de congestion dans ce cas est difficile.Afin de traiter ce problème, nous établissons des résultats sur l'approximation d'un équilibre dans les jeux de congestion et jeux agrégatifs avec un très grand nombre de joueurs et en présence de contraintes couplantes.Ces résultats, obtenus dans le cadre des inégalités variationnelles et sous certaines hypothèses de monotonie, peuvent être utilisés pour calculer un équilibre approché comme solution d'un problème de petite dimension.Toujours dans la perspective de modéliser un très grand nombre d'agents, nous considérons des jeux de congestion nonatomiques avec contraintes couplantes et avec une infinité de joueurs hétérogènes~: ce type de jeux apparaît lorsque les caractéristiques d'une population sont décrites par une fonction de distribution paramétrique.Sous certaines hypothèses de monotonie, nous prouvons que les équilibres de Wardrop de ces jeux, définis comme solutions d'une inégalité variationnelle de dimension infinie, peuvent être approchés par des équilibres de Wardrop symétriques de jeux annexes, solutions d'inégalités variationnelles de petite dimension.Enfin, nous considérons un modèle de jeu pour l'étude d'échanges d'électricité pair-à-pair au sein d'une communauté de consommateurs possédant des actifs de production électrique renouvelable.Nous étudions les équilibres généralisés du jeu obtenu, qui caractérisent les échanges possibles d'énergie et les consommations individuelles.Nous comparons ces équilibres avec la solution centralisée minimisant le coût social, et nous évaluons l'efficacité des équilibres via la notion de prix de l'anarchie. / In the context of smart grid and in the transition to decentralized electric systems, we address the problem of the management of distributed electric consumption flexibilities. We develop different methods based on distributed optimization and game theory approaches.We start by adopting the point of view of a centralized operator in charge of the management of flexibilities for several agents. We provide a distributed and privacy-preserving algorithm to compute consumption profiles for agents that are optimal for the operator.In the proposed method, the individual constraints as well as the individual consumption profile of each agent are never revealed to the operator or the other agents.Then, in a second model, we adopt a more decentralized vision and consider a game theoretic framework for the management of consumption flexibilities.This approach enables, in particular, to take into account the strategic behavior of consumers.Individual objectives are determined by dynamic billing mechanisms, which is motivated by the modeling of congestion effects occurring on time periods receiving a high electricity load from consumers.A relevant class of games in this framework is given by atomic splittable congestion games.We obtain several theoretical results on Nash equilibria for this class of games, and we quantify the efficiency of those equilibria by providing bounds on the price of anarchy.We address the question of the decentralized computation of equilibria in this context by studying the conditions and rates of convergence of the best response and projected gradients algorithms.In practice an operator may deal with a very large number of players, and evaluating the equilibria in a congestion game in this case will be difficult.To address this issue, we give approximation results on the equilibria in congestion and aggregative games with a very large number of players, in the presence of coupling constraints.These results, obtained in the framework of variational inequalities and under some monotonicity conditions, can be used to compute an approximate equilibrium, solution of a small dimension problem.In line with the idea of modeling large populations, we consider nonatomic congestion games with coupling constraints, with an infinity of heterogeneous players: these games arise when the characteristics of a population are described by a parametric density function.Under monotonicity hypotheses, we prove that Wardrop equilibria of such games, given as solutions of an infinite dimensional variational inequality, can be approximated by symmetric Wardrop equilibria of auxiliary games, solutions of low dimension variational inequalities.Again, those results can be the basis of tractable methods to compute an approximate Wardrop equilibrium in a nonatomic infinite-type congestion game.Last, we consider a game model for the study of decentralized peer-to-peer energy exchanges between a community of consumers with renewable production sources.We study the generalized equilibria in this game, which characterize the possible energy trades and associated individual consumptions.We compare the equilibria with the centralized solution minimizing the social cost, and evaluate the efficiency of equilibria through the price of anarchy.