L'augmentation des densités de puissance et d'énergie des SSE (système de stockage électrique) des véhicules électriques/véhicules hybrides rechargeable (VEs/VHRs), tout en conservant des coûts raisonnables pour l'utilisateur, et le développement de convertisseurs d'énergie électrique à haute densité de puissance volumique, et de plus en plus performant vont favoriser la production en masse de véhicules électrifiés. Une partie de ces véhicules électriques (VEs/VHRs) nécessitent une connexion au réseau pour la recharge des batteries. L’insertion de ces nouvelles charges dans le réseau présentera alors plusieurs enjeux et impacts significatifs pour les réseaux électriques puisqu’ils doivent répondre localement à des demandes de puissance non négligeables. Ce projet de thèse vise à étudier et réduire les impacts des VEs/VHRs sur les réseaux de distribution grâce à la technologie Vehicle-to-Grid (V2G). Le véhicule électrique alimente le réseau en fonction des besoins du système électrique (modèle bidirectionnel) et lui offre un service de flexibilité. Ces travaux de recherche ont pour but d'approfondir les concepts dans lequel l’alimentation des véhicules électriques (VE) et/ou hybrides de type P-VEH est intégrée à la gestion du réseau de distribution et des « hubs énergétiques » du futur. L’objectif de la thèse est d’abord étudier les service systèmes possible à fournir grâce à V2G, ensuite de concevoir un système de supervision qui assurera une gestion énergétique de ces nouvelles charges en choisissant le mode de recharge et/ou décharge adéquat et en prenant également en considération la demande de consommation locale et la présence de production de type renouvelable (photovoltaïque, éolien) dans le réseau de distribution. Cette supervision se fera dans un premier temps « en hors ligne » et par la suite « en ligne ». On aura recours à l’utilisation de méthodes d’intelligence artificielle comme l’apprentissage automatique (Machine Learning) et la logique floue, la commande prédictive ainsi que des méthodes d’optimisation hybrides (stochastiques et déterministes). / The power and energy density increment of the electrical storage system (ESS) of electric vehicles/Plug-in hybrid electric vehicles (EVs/PHEVs), while maintaining reasonable costs for the user, and the development of converters of electrical energy to high power density and more and more powerful, will encourage the mass production of electrified vehicles. Beyond, electric vehicles (EVs/PHEVs) require a connection to the grid for the charging of the batteries. The insertion of these new loads in the grid will then present several issues and significant impacts for electrical networks since they must respond locally to non-negligible power requests. This PhD thesis aims to study and reduce the impacts of the EVs/PHEVs on the distribution grid thanks to the vehicle-to-Grid (V2G) technology. The electric vehicle supplies the grid depending on the needs of the electrical system (bi-directional model) and offers a flexible service. These works of research have aimed to deepen the concepts in which the supply of electric vehicles (EV) and/or hybrids of type PHEV is integrated with the management of the distribution network and the future "energy hubs". The objective of the thesis is at first to examine the possible ancillary services provided by V2G, then to design a system of supervision which will ensure an energy management of these new loads by choosing the adequate mode of charge/discharge and also taking into consideration the request of local consumption and the presence of renewable production of type photovoltaic and wind in the distribution grid. This supervision will be in a first step "offline" and subsequently "online". The methods which are used in this thesis are as follows; artificial intelligence such as machine learning and fuzzy logic, the predictive control as well as the methods of hybrids optimization (stochastic and deterministic).

This study aims to examine and quantify the impact from increasing penetration of electric car chargers and solar cells in Mälarenergi's distribution grids. Four different types of low voltage grids are examined: a small rural grid, an older suburban grid, a modern suburban grid and a modern urban grid with multi-dwelling houses. The networks are modeled in Matpower, a MATLAB Power System Simulation Package with grid and metering data from Mälarenergi's NIS (Network Information System), insolation data from Swedish Meteorological and Hydrological Institute (SMHI) and simulated data from an electrical vehicle Home-charing model based on residential activity patterns. The idea has been to use as few assumptions as possible and as much real measurements as possible. The results show that problems such as unwanted voltage levels at the customer's connection points and increasing power flux in the low voltage substation's is to be expected based on aforementioned increasing penetration. The various low voltage networks are affected to varying degrees due to its different structure and type of customers. Measures to increase acceptance for the above mentioned changes have also been reviewed. Line gain shows best properties to reduce both losses and voltage variations. Reactive power compensation in the solar cell's inverters can reduce voltage increases, but with the disadvantage that network losses increase. The use of smart chargers that can control when the charging of electrical vehicles begin charging can both reduce network losses but also the risk of unwanted voltage drops.

The connection of high penetrations of new low carbon technologies such as PV and electric vehicles onto the distribution network is expected to cause power quality problems and the thermal capacity of feeder cables may be exceeded. Replacement of existing infrastructure is costly and so feeder cables are likely to be operated close to their hosting capacity. Network operators therefore require accurate simulation models so that new connection requests are not unnecessarily constrained. This work has reviewed recent studies and found a wide range of assumptions and approximations that are used in network models. A number of these have been investigated further, focussing on methods to specify the impedances of the cable, the impacts of harmonics, the time resolution used to model demand and generation, and assumptions regarding the connectivity of the neutral and ground conductors. The calculation of cable impedances is key to the accuracy of network models but only limited data is available from design standards or manufacturers. Several techniques have been compared in this work to provide guidance on the level of detail that should be included in the impedance model. Network modelling results with accurate impedances are shown to differ from those using published data. The demand data time resolution has been shown to affect estimates of copper losses in network cables. Using analytical methods and simulations, the relationship between errors in the loss estimates and the time resolution has been demonstrated and a method proposed such that the accuracy of loss estimates can be improved. For networks with grounded neutral conductors, accurate modelling requires the resistance of grounding electrodes to be taken into account. Existing methods either make approximations to the equivalent circuit or suffer from convergence problems. A new method has been proposed which resolves these difficulties and allows realistic scenarios with both grounded and ungrounded nodes to be modelled. In addition to the development of models, the voltages and currents in a section of LV feeder cable have been measured. The results provide a validation of the impedance calculations and also highlight practical difficulties associated with comparing simulation models with real measurement results.

The total energy demand in the world is expected to increase in the future years due to thehigh development rate of developing countries. Access to energy enables development, butthe current global energy mix has to be modified if a sustainable growth is desired. Renewableenergy sources (RES) benefit from both a political and economic support from manygovernments and international entities. The growing installation of RES takes place both inlarge scale, as wind farms with sizes 10 – 1000 MW, and in small scale in homes or smallenterprises with sizes 100 W – 100 kW. Small scale wind power connected to the grid is rarenowadays except in the case of remote mini-grids. By contrast, small scale solar photovoltaic(PV) power is being more and more commonly installed, especially in the form of investorownedroof-installed units. Taking increasing small scale solar and wind power into accountin network planning is a challenge faced by the distribution system operator (DSO).The aim of this thesis is to present a guideline that assists DSOs when planning lowvoltage (LV) distribution networks (DN) with a large amount of small scale distributedgeneration (DG) on a short-term perspective. A review on integration issues of DG isperformed and over-voltage constraints are identified as the most relevant issue. Simple ruleshave already been designed for individual DG units, as the one presented in the AMKhandbookpublished by Svensk Energi; but these are not valid any more when consideringmore than one DG unit. The new proposed guideline employs the AMK-handbook as astarting point and develops it further by including the interaction between DG units. Theguideline is then applicable to scenarios with more than one DG unit. The maximum capacityof a new DG unit applying for a connection to a grid is calculated based on the location andcapacity of the already installed DG units, and without any reinforcement. The proposedguideline can be applied under no load and minimum load condition.Since this thesis is a collaboration project between KTH-Royal Institute of Technologyand Vattenfall R&D, two specific Swedish LV distribution networks owned by VattenfallEldistribution AB are studied. Scenarios with different penetration levels of DG, with valuesbetween 12% and 71%, and capacity of individual DG units below 43.5 kW are analyzed.Evaluation of the results shows that the proposed guideline leads to acceptable results. Thedevelopment of future simple guidelines is suggested to be based on the following twoaspects: absolute and relative location of the DG units; and a correct identification of the weakbus. Relative location reveals the interaction with other DG units within the DN. Moreover, itis stated that the use of the penetration level as a planning measure, based on the total DGcapacity, has a limited application.

The electric power industry and society are facing the challenges and opportunities of transforming the present power grid into a smart grid. To meet these challenges, new types of control systems are connected over IT infrastructures. While this is done to meet highly set economical and environmental goals, it also introduces new sources of uncertainty in the control loops. In this thesis, we consider control design taking some of these uncertainties into account. In Part I of the thesis, some economical and environmental concerns in smart grids are taken into account, and a scheduling framework for static loads (e.g., smart appliances in residential areas) and dynamic loads (e.g., energy storage systems) in the distribution level is investigated. A robust formulation is proposed taking the user behavior uncertainty into account, so that the optimal scheduling cost is less sensitive to unpredictable changes in user preferences. In addition, a novel distributed algorithm for the studied scheduling framework is proposed, which aims at minimizing the aggregated electricity cost of a network of apartments sharing an energy storage system. We point out that the proposed scheduling framework is applicable to various uncertainty sources, storage technologies, and programmable electrical loads. In Part II of the thesis, we study smart grid uncertainty resulting from possible security threats. Smart grids are one of the most complex cyber-physical systems considered, and are vulnerable to various cyber and physical attacks. The attack scenarios consider cyber adversaries that may corrupt a few measurements and reference signals, which may degrade the system’s reliability and even destabilize the voltage magnitudes. In addition, a practical attack-resilient framework for networked control systems is proposed. This framework includes security information analytics to detect attacks and a resiliency policy to improve the performance of the system running under the attack. Stability and optimal performance of the networked control system under attack and by applying the proposed framework, is proved here. The framework has been applied to an energy management system and its efficiency is demonstrated on a critical attack scenario. / <p>QC 20160830</p>

The content of this Master´s Thesis is creating of dynamic models of distributed energy sources in PSCAD and their validation in chosen operation regimes. In the introduction of this thesis is summarized theoretical knowledge about methods for power systems analysis and there is a comparison of static and dynamic methods for power systems analysis. Static methods are used to calculate electric variables in grid nodes. In compare with them, dynamic methods are used to study instantaneous electrical and mechanical variables not only in grid nodes, but also at components of power system. Secondly, we individually designed distributed energy sources in according to requirements, we made a topology of distribution grid and we integrated these energy sources to the distribution grid. Finally, we chose some operation regimes, and studied a behavior of energy sources during these operation regimes.

The content of this Master´s Thesis is creating of dynamic models of distributed energy sources in PSCAD and their validation in chosen operation regimes. In the introduction of this thesis is summarized theoretical knowledge about methods for power systems analysis and there is a comparison of static and dynamic methods for power systems analysis. Static methods are used to calculate electric variables in grid nodes. In compare with them, dynamic methods are used to study instantaneous electrical and mechanical variables not only in grid nodes, but also at components of power system. Secondly, we individually designed distributed energy sources in according to requirements, we made a topology of distribution grid and we integrated these energy sources to the distribution grid. Finally, we chose some operation regimes, and studied a behavior of energy sources during these operation regimes.

The number of electrical vehicles in Sweden are increasing faster for every year and the demand of charging them at home is growing as well. This requires high delivery reliability and a stable low-voltage distribution grid. In this master thesis three different low-voltage networks are modelled and simulated together with load which corresponds home charging of electrical vehicles (EV) to analyse if the grid is able to handle these kinds of stresses. Information of the different grids were gathered from Falu Energi &amp; Vatten and modelled in Matlab together with EV charging loads generated in a separate program. The electricity consumption data used in the simulations were measured at the transformer in each grid. A regression analysis of the consumption data were preformed to calculate values which corresponds to a worst case scenario. The results show that the low-voltage distribution grid in Falun is well dimensioned and can handle these possible future loads even in the worst constructed scenario.

Dans cette thèse, les mesures de tension fournies par l'infrastructure de comptage avancé (Advanced Metering Infrastructure, AMI) sont utilisées pour contrôler un régleur en charge situé à la sous station HTA/BT. La thèse présente une méthode simple permettant de sélectionner les clients basse tension pour lesquels les mesures de tension sont utilisées comme une entrée au contrôleur du régleur en charge. Le procédé mis au point tient compte de la charge et de la topologie du réseau. En outre, une méthode simple pour créer des courbes réalistes et statistiquement correctes pour les études de réseaux est présenté. Les méthodes créées ont été testées en utilisant des données réelles de réseaux basse tension sur un logiciel très utilisé dans le secteur de la distribution d'électricité ont conduit à des résultats encourageants; quelques clients par réseau basse tension doivent être surveillés afin d’estimer avec une grande précision où se situe les extremums de tension sur le réseau.Cette méthodologie est également utilisée pour estimer la capacité d'accueil de génération d'énergie photovoltaïque dans un réseau à basse tension donné.Dans la première partie, l'évolution de la capacité d'accueil en utilisant trois types de contrôle de tension différents; un régleur en charge de cinq et neuf positions et le contrôle de la tension à travers les générateurs photovoltaïques, sont étudiés. L'étude considère deux cas différents pour le placement et le dimensionnement des générateurs photovoltaïques dans un réseau basse tension. Les résultats sur 38 réseaux basse tension sont fournis.Dans la deuxième partie, les capacités d'accueil de 631 réseaux basse tension, situés dans une région métropolitaine française, sont analysés en utilisant un régleur en charge de cinq et neuf positions.Le travail a été réalisé en collaboration avec Électricité Réseau Distribution France (ERDF), le principal opérateur du réseau de distribution français. Toutes les études présentées dans la thèse reposent sur les données réelles de fonctionnement normal. En outre, toutes les études sont mises en œuvre sur un logiciel largement utilisé dans l'industrie de la distribution d'énergie.Comme une partie introductive aux réseaux basse tension, la thèse fournit une vue générale sur le système électrique français. De plus, la thèse présente un certain nombre de technologies sélectionnés en tenant compte des réseaux basse-tension qui semblent prometteurs pour le futur. / In this thesis, voltage measurements provided by the advanced metering infrastructure (AMI) are used to control an on-load tap changer located at the secondary substation. The thesis presents a practical and a straightforward method of selecting the low voltage customers whose voltage measurements are used as an input to the controller of the on-load tap changer. The developed method takes into account the load and the topology of the network. Furthermore, a simple method of creating synthetic and statistically correct load curves for networks studies is presented. The created methods have been tested by using real data of low voltage networks on a common platform in the power distribution industry leading to encouraging results; a few customers per low voltage network should be monitored in order to achieve accurate voltage measurements.This methodology is further applied to estimate the hosting capacity of photovoltaic power generation in a given low voltage network.In the first part, the evolution of the hosting capacity by using three different types of voltage control; an on-load tap changer of five and nine tap positions and voltage control through photovoltaic power generators, is studied. The study considers two different cases for placing and sizing the photovoltaic generators in a low voltage network. The results of 38 low voltage networks are provided.In the second part, the hosting capacities of 631 low voltage networks, located in a French metropolitan area, are analysed by using an on-load tap changer of five and an on-load tap changer of nine tap positions.The work has been together with Électricité Réseau Distribution France (ERDF), the major French distribution system operator. All studies presented in the thesis are based on the real operational data of the company. Moreover, all studies are implemented on a platform that is widely used in the power distribution industry.As an introductory part to low voltage networks, the thesis provides a general view about the French power system. In addition, the thesis presents a number of selected technologies considering low voltage networks that seem promising in the future.

This thesis is focused on demonstrating the impact of the implementation of decentralized distributed energy sources (mainly RES) and electromobility technologies to electrical parameters in Czech medium voltage distribution network. Thesis is divided into two main chapters. First one is a brief theoretical summary of this problematic and the second one is a practical software simulation on a real medium voltage network. Proposed implementation scenarios are based on EU and national strategic plans for time period from 2020 to 2040.