Dissertations / Theses on the topic 'And Grid Code'

A rapid development of offshore wind power is planned in GB as a part to fulfil the EU2020 targets. 25 GW wind power capacity has been awarded to developers in nine different offshore zones outside the coast of UK. VSC-HVDC transmission is expected to be a both technical and economical favourable solution for transmitting the power into the main grid. This study investigates if such a transmission solution could comply with the regulatory framework in UK. Vattenfall and Scottish Energy Renewable will be part of this development and have been awarded the rights to develop 7200 MW of wind capacity outside the cost of East Anglia as a part of the offshore expansion plans in UK. The zone is broken down to several projects. The first project is called East Anglia ONE and this project is used as a reference case in this study. The GB Grid Code has been broken down into four areas, voltage and frequency variations; fault ride through requirements, active power control and reactive power control. Load flow calculations and dynamic simulations are designed to investigate compliance of each area. Further, simulations to investigate the interaction between the wind turbines and the offshore converter stations where done. A model representing East Anglia ONE was built in PSS/E and used to investigate grid codes compliance by load flow calculations and dynamic simulations. Data from earlier studies at Vattenfall was used to get a good representation of the wind park. A model representing a HVDC-transmission solution was provided by ABB. The results from load flow calculations and simulations show that a HVDC-solution can comply with the investigated parts of the grid codes. The limiting factor seems to be the capability to inject enough reactive power to the gird at small voltage dips during normal operation. This capability can, however, be enhanced with the right tap-changer settings at the onshore converter transformer.

The trend towards harmonizing grid codes within Europe will increase the demands for grid code compliance. Wind power is for several reasons not comparable to conventional power generation but will, due to large installations, need to show compliance with the grid codes. This thesis is investigating grid code requirements as proposed by National Grid (UK) and ENTSO-E. Modelling work and simulations have also been performed to investigate the grid ode compliance of Thanet offshore wind farm in UK. The work has been about investigating frequency response and fault-ride-through criterion and shows that grid codes are fulfilled in Thanet but that the model requires further work.

Since its introduction in 1997, the use of Detached Eddy Simulation (DES) and similar hybrid turbulence techniques has become increasingly popular in the field of CFD. However, with increased use some of the limitations of the DES model have become apparent. One of these is the dependence of DES on grid construction, particularly regarding the point of transition between the Reynolds-Averaged Navier-Stokes and Large Eddy Simulation models. An additional issue that arises with unstructured grids is the definition of the grid spacing in the implementation of a DES length scale. To lay the ground work to study these effects the Spalart-Allmaras one-equation turbulence model, SA based DES hybrid turbulence model, and the Scale Adaptive Simulation hybrid turbulence model are implemented in an unstructured grid CFD code, UNCLE. The implemented SA based DES model is validated for flow over a three-dimensional circular cylinder for three different turbulent Reynolds numbers. Validation included studying the pressure, skin friction coefficient, centerline velocity distributions averaged in time and space. Tools to output the mean velocity profiles and Reynolds stresses were developed. A grid generation code was written to generate a two/three dimensional circular cylinder grid to simulate flow over the cylinder in UNCLE. The models implemented and validated, and the additional tools mentioned will be used in the future.

Cette thèse a pour cadre les transmissions sur les réseaux CPL-BE et les réseaux de capteurs à faible capacité. L'état de l'art classique sur la protection de l'information dans la transmission par réseaux de capteurs fait référence à l'utilisation de codage distribué où les relais implémentent des opérations de parité (mélange des flux) sur les data issues des capteurs. Cependant, il est difficile, de par la nature variable de la qualité des liens en liaisons sans fil, de contrôler la qualité du codeur équivalent construit et de maintenir ses performances au cours du temps. C'est pourquoi nous nous sommes orientés dans cette thèse vers la recherche de schémas de codage différents qui résistent mieux à la variation de qualité des liaisons à travers le réseau. Notre choix s'est porté sur le codage par sous-espace inspiré des travaux de Gabidulin. Le but est de former un code qui utilise une métrique simple et résistante pour sécuriser les transmissions sur le réseau. Les codes à métrique de rang répondent bien à ce besoin car il n'y a qu'à contrôler le rang de la matrice obtenue en réception pour vérifier l'intégrité de la transmission. Les codes à métrique de rang et leur algorithme de décodage ont été étudiés dans un premier temps. Puis, les performances du code LRPC proposé concaténé avec les codes convolutifs sont testées dans des schémas de transmission des contextes différents
This thesis considers the context of transmissions on CPL-BE networks and low-capacity sensor networks. The state of the art on information protection intransmission by sensor networks refers to the use of distributed coding, where therelays implement parity operations (mixing of streams) on data transmitted by thesensors. However, due to the varying nature of the quality of the wireless links, it is difficult to control the quality of the equivalent encoder constructed and to maintain its performance over time. Therefore, in this thesis, we have focused on the search for different coding schemes that are better resist the variation in the quality of the links across the network. Our choice was based on the sub-space coding inspired by Gabidulin's work. The goal is to form a code that uses a simple and resistant metric to secure transmission across the network. Rank metric codes respond well to this need because it only has to control the rank of the matrix obtained in reception to verify the integrity of the transmission. The rank metric codes and their decoding algorithm were studied in a first step. Then, the performance of the proposed LRPC code concatenated with the convolutional codes is tested in transmission schemes of different contexts

Les travaux de recherche présentésdans cette thèse ont été effectués dans le cadred'une collaboration entre Leroy Somer et lelaboratoire de génie électrique et électronique deParis (GeePs). Ils ont pour objectif lessimulations des phénomènes observés en modetransitoire des machines électriques. Cessimulations sont particulièrement orientées parles nouvelles exigences issues du Grid Code pourles alternateurs connectés au réseau.Principalement, deux types de modèles ont étédéveloppés. Le premier se base sur unereprésentation de l’état magnétique de lamachine où chaque flux est exprimé en fonctiondes courants des différentes bobines. Le secondmodèle regroupe les courants en utilisant descourants magnétisants sur les axes d et q associésà des coefficients de saturation pour chaque fluxet simplifie la représentation magnétique,notamment pour la prise encompte du circuit amortisseur. Avec unemodélisation suffisamment précise ducomportement magnétique non linéaire de lamachine, ils permettent de mieux prédire lescourants et le couple électromagnétique lors desdéfauts tels que les creux de tension. Les travauxeffectués présentés dans ce mémoire ont permis,en partant des descriptions des saturationstrouvées dans une machine, de définir desméthodes pour incorporer la saturation dans lesmodèles de type circuit et finalement d’aboutirau choix du modèle non-linéaire pour unemachine électrique donnée. Grâce à un temps decalcul réduit, ils ont aussi conduit à l'intégrationsous Simulink de modèles de la machine et dusystème d'entrainement pour la réalisationd'études de stabilité et pour créer unenvironnement de mise au point de la commandedu système
The research presented in this thesiswas carried out in the research and developmentproject between Leroy Somer and the Group ofElectrical Engineering of Paris (GeePs). Theirobjective is to simulate the phenomena observedin the transient states of electrical machines.These simulations are particularly oriented bythe new Grid Code requirements for alternatorsconnected to the power network. Two types ofmodels have been principally developed. Thefirst one is based on a magnetic description ofthe machine where each flux is expressed as afunction of the currents flowing through thedifferent machine windings. The second oneregroups the different winding currents by usingthe magnetizing currents on axes d and qassociated to saturation coefficients for eachflux linkage and simplifies the magneticdescription, especially when taking into accountthe damper windings. With a sufficiently precisemodelling of the non-linear magnetic behaviourof the machine, it is possible to better predict thecurrents and the electromagnetic torque underfault conditions such as voltage drops. The workcarried out in this thesis has made possible,starting from the descriptions of the saturationeffects found in a machine, to define methodsfor incorporating saturation into circuit models.Finally, one can make a choice of the dynamicnon-linear model for a given machine. Thanks toshort computation time, it also led to theSimulink integration of the machine andexcitation system models paving the way forstability and control studies

The thesis is concerned with the study of the dynamic responses of a supercritical coal-fired power plant via mathematical modelling and simulation. Supercritical technology leads to much more efficient energy conversion compared with subcritical power generation technology so it is considered to be a viable option from the economic and environmental aspects for replacement of aged thermal power plants in the United Kingdom. However there are concerns for the adoption of this technology as it is unclear whether the dynamic responses of supercritical power plants can meet the Great Britain Grid Code requirement in frequency responses and frequency control. To provide answers to the above concerns, the PhD research project is conducted with the following objectives: to study the dynamic responses of the power plant under different control modes in order to assess its compliance in providing the frequency control services specified by the Great Britain Grid Code; to evaluate and improve the performance of the existing control loops of the power plant simulator and in this regard a controller based on the Dynamic Matrix Control algorithm was designed to regulate the coal flow rate and another controller based on the Generalized Predictive Control algorithm was implemented to regulate the temperature of the superheated steam; to conduct an investigation regarding frequency control at the power plant level followed by an analysis of the frequency control requirements extracted from the Grid Codes of several European and non-European countries. The structure and operation of the supercritical power plant was intensively studied and presented. All the simulation tests presented in this thesis were carried out by the mean of a complex 600 megawatts power plant simulator developed in collaboration with Tsinghua University from Beijing, China. The study of the conducted simulation tests indicate that it is difficult for this type of power plant to comply with the frequency control requirements of the Great Britain Grid Code in its current control method. Therefore, it is essential to investigate more effective control strategies aiming at improving its dynamic responses. In the thesis, new Model Predictive Control power plant control strategies are developed and the performance of the control loops and consequently of the power plant are greatly improved through implementation of Model Predictive Control based controllers.

Nordex, a wind-turbine manufacturer and developer, has just launched the development activity over Belgium’s French-speaking Region – the Walloon Region – with the current political context favorable to wind energy deployment. Since the Walloon market is unknown, the master thesis aims to identify the appropriate approach to use for optimal wind farm development and the critical issues that may impinge on it. The scope of the master thesis is thus to find two to three sites well suited for wind farm implementation in the province of Luxembourg and to develop these sites.  An exhaustive study of the wind farm potential of the province of Luxembourg has been led, based on geographic data analysis with the GIS ArcGIS®, feasibility studies conducting, meetings with districts’ administration as well as visits onsite. In addition, a thorough comparative analysis of the Belgian specification for grid connection has been performed to identify any requirement that is not included in the French and German grid codes, which are the benchmarks of the development activity in Nordex France. Many obstacles have been encountered in wind farm development, chiefly a strong existing competition in the wind energy sector and a limited grid capacity. In addition time can be a friend but it can also sometimes be a foe at some stages that rely on public administration. Consequently from the 40 identified sites with ArcGIS®, only three have succeeded. Regarding the Belgian requirements for grid connection, all can be met thanks to an existing German specification data sheet. Eventually the Walloon policy towards wind energy development is expected to evolve so as to foster wind farm deployment in Wallonia and to reach the objectives set for 2020 (2200 MW of installed wind capacity while in January 2011 only 440 MW were in operation). Consequently to that, Nordex’ approach may have to adapt to the new regulations.

A three-dimensional unstructured incompressible RANS code has been developed using artificial compressibility and Spalart-Allmaras eddy viscosity model. A node-based finite volume method is used in which all flow variables are defined at the vertices of tetrahedrons in an unstructured grid. The inviscid fluxes are computed by using the Roe's flux difference splitting method, and higher order accuracy is attained by data reconstruction based on Taylor series expansion. Gauss theorem is used to formulate necessary gradients. For time integration, an implicit scheme based on linearized Euler backward method is used. A tetrahedral unstructured grid generation code has been also developed and applied to the tip clearance flow in a highly staggered cascade. Surface grids are first generated in the flow passage and blade tip by using several triangulation methods including Delaunay triangulation, advancing front method and advancing layer method. Then the whole computational domain including tip gap region is filled with prisms using the surface grids. Each prism is divided into three tetrahedrons. To accomplish this division in a consistent manner, connectivity pattern is assigned to each triangle in the surface grids. A new algorithm is devised to assign the connectivity pattern without reference to the particular method of triangulation. This technique offers great flexibility in surface grid generation. The code has been validated by comparisons with available computational and experimental results for several test cases: invisicd flow around NACA section, laminar and turbulent flow over a flat plate, turbulent flow through double-circular arc cascade and laminar flow through a square duct with 90° bend. For the laminar flat plate case, the velocity profile and skin friction coefficient are in excellent agreement with Blasius solution. For the turbulent flat plate case, velocity profiles are in full agreement with the law of the wall up to Reynolds number of 1.0E8, however, the skin friction coefficient is under-predicted by about 10% in comparison with empirical formula. Blade loading for the two-dimensional circular arc cascade is also compared with experiments. The results obtained with the experimental inflow angle (51.5° ) show some discrepancies at the trailing edge and severely under-predict the suction peak at the leading edge. These discrepancies are completely remedied if the inflow angle is increased to 53.5° . The code is also capable of predicting the secondary flow in the square duct with 90° bend, and the velocity profiles are in good agreement with measurements and published Navier-Stokes computations. Finally the code is applied to a linear cascade that has GE rotor B section with tip clearance and a high stagger angle of 56.9° . The overall structure of the tip clearance flow is well predicted. Loss of loading due to tip leakage flow and reloading due to tip leakage vortex are presented. On the end wall, separation line of the tip leakage vortex and reattachment line of passage vortex are identified. The location of the tip leakage vortex in the passage agrees very well with oil flow visualization. Separation bubble on the blade tip is also predicted. Mean streamwise velocity contours and cross sectional velocity vectors are compared with experimental results in the near wake, and good agreements are observed. It is concluded that Spalart-Allmaras turbulence model is adequate for this type of flow field except at locations where the tip leakage vortex of one blade interacts with the wake of a following blade. This situation may prevail for blades with longer span and/or in the far wake. Prediction of such an interaction presents a challenge to RANS computations. The effects of blade span on the flow structure have been also investigated. Two cascades with blades of aspect ratios of 0.5 and 1.0 are considered. By comparing pressure distributions on the blade, it is shown that the aspect ratio has strong effects on loading distribution on the blade although the tip gap height is very small (0.016 chord). Grid convergence study has been carried out with three different grids for pressure distributions and limiting streamlines on the end wall.
Ph. D.

The continuously increasing energy penetration from wind farms into the grid raises concerns regarding power quality and the stable operation of the power system. The Grid Code´s requirements give strict guidelines for a wind farm´s behaviour under faulty or abnormal operating conditions.The primary purpose of this project is the application of a STATCOM for wind farm integration complying with the Grid Code. Towards that, an outer control strategy for the converter is designed so as to regulate the voltage at the point of common coupling by providing reactive power compensation. Thus the safe operation of the grid will be ensured since the wind farm will follow the Grid Code´s standards.The existing Grid Code requires only a positive sequence current controller. This study attempts to investigate whether this is sufficient or not and to examine the possibility of extending the Grid Code requirements so as to incorporate a negative sequence current controller as well. The results support the latter suggestion. Also, the use of SiC devices was also considered in this project.
Den ständigt ökande penetrationen av vindenergi i elnätet väcker farhågor om elkvalitet och stabil drift av kraftsystemet. Nätkoden (Grid Code) ger strikta riktlinjer för en vindkraftsparks beteende i felfall och under onormala driftsförhållanden.Huvudsyftet med detta projekt är att använda en STATCOM för integration av vindkraftsparker så att nätkoden uppfylls. I detta projekt utformas en yttre reglerstrategi för omriktaren för att reglera spänningen vid anslutningspunkten för vindkraftsparken genom att tillhandahålla reaktiv effektkompensering. Därigenom uppnås en säker drift av nätet eftersom vindkraftparken kommer att följa nätkoden.Den befintliga nätkoden kräver endast styrning av plusföljdskomponenten av strömmen. Denna studie försöker undersöka om detta är tillräckligt samt undersöka möjligheten för att utvidga nätkoden genom att införa ett krav på styrning av negativ-sekvens ström. Resultaten stöder det sistnämnda förslaget. Även användningen av halvledarkomponenter av kiselkarbid-SiC studerades i detta projekt.

Approved for public release; distribution is unlimited
The Numerical Electromagnetics Code (NEC) was used to evaluate the admittance, average power gain, and the electric near and far field of a monopole antenna mounted on a cubical box over a perfectly conducting ground plane. Two models of the box, employing surface patches and wire grids, were evaluated. The monopole was positioned at the center, the edge, and at a corner of the box's top surface. Admittance and average power gain of the antenna were calculated. NEC results were examined and compared with experimental data and with results from "PATCH", another independent electromagnetic modeling code. The near electric field was calculated for both models. Computer graphics techniques were presented for plotting NEC near field results using DISSPLA (Display Integrated Software System and Plotting Language), a commercial graphics package. Contour and 3-D amplitude, and phase plots of the near electric fields were presented. Radiation patterns were calculated to relate far field and near field behavior of the antenna. Surface patch and wire grid models are compared and conclusions were presented.
Naval Ocean Systems Center
http://archive.org/details/investigationofn00elli
O&MN, Direct Funding
Lieutenant, Hellenic Navy

Grid codes are becoming more demanding on power generating units due to the factthat the complexity of the power grid is increasing. The penetration of wind powerhas grown over the last years and it is clear that wind farms need to be addressedwith the same type of grid codes as conventional generation units. There is howeveran undeniable difference between the technology in conventional synchronousgeneration units, and the asynchronous generation units in wind farms. This thesis has reviewed the current grid code in Sweden and compared it to the newcode proposed by ENTSO-E, “the Requirements for Generators”, in the aspect ofwind farms with an installed power of 30 MW or more. The comparison has beencomplemented by an analysis of how wind farms of two different technologies(Doubly fed induction generators and full power converters) can meet therequirements and technical proposals have been given on how to be able to meetcompliance with the new grid codes. The Requirements for Generators contains many non-exhaustive and optionalrequirements, because of this it has been difficult to, at this stage, exactly point outthe technical impact on the grid connection of future wind farms in Sweden. For manyof the requirements in the Requirements for Generators there is no equivalent in theSwedish Grid Code (SvK FS2005:2) but counterparts can thus be found in existingpractices and therefor does not imply any major differences for the industry. The requirements of frequency regulation, synthetic inertia and reactive powercapability are the main components of the RfG which will require additional softwareand hardware installations for future wind farms in Sweden.

The aim of this Master thesis is to choose appropriate authentication method for logging in to the electronic banking. The chosen solution will serve as an additional factor for authentication and authorization of client and at the same time as the replacement of the outdated security method GRID card. Development and direction of the electronic banking is explained in the theoretical part of the thesis. Further on, the advantages of this channel that are provided to clients and bank, are described. Some of the trends which daily affect the direction of the electronic banking are also described. Security is very important part of the electronic banking and that is why it is mentioned in the each part of this thesis. The practical part contains proposed cancellation procedure of GRID cards and proposal of the new solutions that could replace them in the future. It also contains selection and description of evaluation criteria and multi-criteria evaluation of the selected solutions. Saaty method and scoring method were used to determine the weight of the particular criteria. Conclusion of the thesis compares achieved results of the individual authentication methods and assets of this Master thesis.

The understanding of the physics of the Coherent Structures and their interaction with the remaining fluid motions is of paramount interest in Turbulence Research.

Indeed, recently had been suggested that separating and understanding the the different physical behavior of Coherent Structures and "uncoherent" background might very well be the key to understand and predict Turbulence. Available understanding of Coherent Structures shows that their size is considerably larger than the turbulent macro-scale, making permissible the application of Large Eddy Simulation to their simulation and study, with the advantage to be able to study their behavior at higher Re and more complex geometry than a Direct Numerical Simulation would normally allow. Original purpose of the present work was therefore the validation of the use of Large Eddy Simulation for the study of Coherent Structures in Shear-Layer and the its application to different flow cases to study the effect of the flow topology on the Coherent Structures nature.

However, during the investigation of the presence of Coherent Structures in numerically generated LES flow fields, the aging in house Large Eddy Simulation (LES) code of the Environmental & Applied Fluid Dynamics Department has shown a series of limitations and shortcomings that led to the decision of relegating it to the status of Legacy Code (from now on indicated as VKI LES legacy code and of discontinuing its development. A new natively parallel LES solver has then been developed in the VKI Environmental & Applied Fluid Dynamics Department, where all the shortcomings of the legacy code have been addressed and modern software technologies have been adopted both for the solver and the surrounding infrastructure, delivering a complete framework based exclusively on Free and Open Source Software (FOSS ) to maximize portability and avoid any dependency from commercial products. The new parallel LES solver retains some basic characteristics of the old legacy code to provide continuity with the past (Finite Differences, Staggered Grid arrangement, Multi Domain technique, grid conformity across domains), but improve in almost all the remaining aspects: the flow can now have all the three directions of inhomogeneity, against the only two of the past, the pressure equation can be solved using a three point stencil for improved accuracy, and the viscous terms and convective terms can be computed using the Computer Algebra System Maxima, to derive discretized formulas in an automatic way.

For the convective terms, High Resolution Central Schemes have been adapted to the three-dimensional Staggered Grid Arrangement from a collocated bi-dimensional one, and a system of Master-Slave simulations has been developed to run in parallel a Slave simulation (on 1 Processing Element) for generating the inlet data for the Master simulation (n - 1 Processing Elements). The code can perform Automatic Run-Time Load Balancing, Domain Auto-Partitioning, has embedded documentation (doxygen), has a CVS repository (version managing) for ease of use of new and old developers.

As part of the new Frame Work, a set of Visual Programs have been provided for IBM Open Data eXplorer (OpenDX), a powerful FOSS Flow visualization and analysis tool, aimed as a replacement for the commercial TecplotTM, and a bug tracking mechanism via Bugzilla and cooperative forum resources (phpBB) for developers and users alike. The new M.i.O.m.a. (MiOma) Solver is ready to be used again for Coherent Structures analysis in the near future.
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished

This thesis deals with the compliance of fixed speed and variable speed wind turbines based on doubly fed induction generator (DFIG) with the new UK grid code in terms of reactive power capability and fault ride through capability. Moreover, a new technique which enables the converter rating reduction of the DFIG based on variable frequency operation is proposed and evaluated in this thesis.

This thesis is concerned with the Internalization of Norms and their Regularization in the Swedish Penal Code - A Repertory Grid Study of Cognitive and Affective Reactions in Men Sentenced to Imprisonment for Sexual Crimes. The research, taking on a phenomenological approach, is an indepth study which set out to explore the thinking of sexual offenders. A constructivist perspective on thinking underpins the research. Constructs are seen as the means that enable the individual to anticipate future events and make the person act in accordance with a societal norm system. George Kelly's Personal Construct Theory provided useful tools to find channels to the thoughts that may explain the offenders' criminal behaviour. The method, focusing on the participants' construing of their reality and not on the crimes committed, made these men talk. The constructs produced were elicited from the element set of important people in their lives. Failing norms may be regarded as wrongly internalized constructions that the offenders have built on previous experiences. There are indications in the results that disturbed behaviour and a lack of norms are linked to childhood neglect and a malfunctioning relationship to the mother. The findings also indicate that deviant behaviour may be due to deficiencies in the capacity for thinking. The situation and the problems of these perpetrators are known but the psychological treatment currently provided by the Swedish Prison and Probation Administration is insufficient. A constructivist treatment program, in order to change thoughts and attitudes of offenders, could form part of a rehabilitation treatment. In addition, focusing on the importance of early internalization of societal norms and on the implications of different forms of neglect in childhood may help to prevent crimes.

The focus of this thesis work was the development of an approachto couple a previosly existing Thermal Energy Storage (TES) modelwritten in C++ with a Simulink/Simscape plant model to simulate anAdvanced Adiabatic Compressed Air Energy Storage (AA-CAES) plant.After the creation and validation of such tool, the complete modelwas used to run simulations, with the aim of assessing the AA-CAESplant's performance under multiple patterns of charge anddischarge.Most of the works found in the literature only provide values ofstorage efficiency obtained from analytical approaches, whilethose that use simulation tools provide average values ofefficiencies when the plant is performing a series of identicalcycles of charge and discharge. During this thesis project,instead, simulations were performed for consecutive irregularcycles determined as the plant response to the electric grid powerrequest. The average efficiency values obtained provide thereforea better representation of how the plant would perform in realapplications.The results show that, under the assumptions made, the AA-CAESplant's overall storage efficiency is influenced very weakly byalterations of the charge-discharge patterns, and that goodperformances can be expected not only for identical chargedischargeconsucutive cycles, but for any pattern that observesthe cavern pressure limits, as long as the thermal energy storageis sized wisely.In addition, a sensitivity analysis was performed in order toassess the influence of turbomachinery efficiency on overallstorage efficiency, for a specified plant layout. The results showthat the turbine efficiency is the most affecting parameter to theplant's performance, while the impact of the main compressors'sinefficiency is mitigated by the thermal recovery that takes placein the TES.The present work confirms that AA-CAES is a promising technologyand that storage efficiencies above 70% can be achieved even inrealistic production scenarios.Finally, future steps for more accurate simulations of plants'performances and more detailed energy production scenarios areproposed.MSc ET 18007Examinator: Joakim WidénÄmnesgranskare: Ane HåkanssonHandledare:

The integration of dispatchable renewable energies like biomass, geothermal and reservoir hydro technologies into an electrical network present no greater challenge than the integration of conventional power technologies for which are well understood by Eskom engineers. However, renewable energies that are based on resources that fluctuate throughout the day and from season to season, like wind and solar, introduce a number of challenges that Eskom engineers have not dealt with before. It is current practice for Eskom‟s generation to follow the load in order to balance the demand and supply. Through Eskom‟s load dispatching desk at National Control, generator outputs are adjusted on an hourly basis with balancing reserves making up only a small fraction of the total generation. Through the Integrated Resource Plan for Electricity of 2010, the Department of Energy has set some targets towards integrating renewable energy, including wind and solar generation, into the South African electricity market consequently introducing variability on the supply side. With demand that varies continually, maintaining a steady balance between supply and demand is already a challenging task. When the supply also becomes variable and less certain with the introduction of non-dispatchable renewable energy, the task becomes even more challenging. The aim of this research study is to determine whether the resources that previously helped to balance the variability in demand will still be adequate to balance variability in both demand and supply. The study will only concentrate on variable or non-dispatchable renewable energies as will be added to the South African electrical network according to the first two rounds of the Department of Energy‟s Renewable Energy Independent Power Producer Procurement Programme. This research study only looks into the balancing challenge and does not go into an analysis of voltage stability or network adequacy, both of which warrant in depth analysis.
Thesis (MIng (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2013.

Analysis of unsteady flows is a very challenging topic of research. A decade ago, potential flow equations were used to predict unsteady pressures on oscillating bodies. Recognising the fact that nonlinear aerodynamics is essential to analyse unsteady flows accurately, particularly in transonic and supersonic flows, different Euler formulations operating on moving grids have emerged recently as important CFD tools for unsteady aerodynamics. Numerical solution of Euler equations on moving grids based on upwind schemes such as the ones due to van Leer and Roe have been developed for the purpose of numerical simulation of unsteady transonic and supersonic flows. In the present work, Euler computations based on yet another recent robust upwind scheme (for steady flows) namely Kinetic Flux Vector Splitting (KFVS) scheme due to Deshpande and Mandal is chosen for further development of a time accurate Euler solver to operate on problems involving moving boundaries. The development of an Euler code based on this scheme is likely to be highly useful to analyse problems of unsteady aerodynamics and computational aeroelasiticity especially when it is noted that KFVS has been found to be an extremely robust scheme for computation of subsonic, transonic, supersonic and hypersonic flows. The KFVS scheme, basically exploits the connection between the linear scalar Boltzmann equation of kinetic theory of gases and the nonlinear vector conservation law, that is, Euler equations of fluid dynamics through moment method strategy. The KFVS scheme has inherent simplicity in splitting the flux even on moving grids due to underlying particle model. The inherent simplicity of KFVS for moving grid problems is due to its relationship with the Boltzmann equation. If a surface is moving with velocity w and a particle has velocity v, then it is quite reasonable to do the splitting based on (v-w)<0 or >0. Only particles having velocity v greater than w will cross the moving surface from left to right and similar arguments hold good for particles moving in opposite direction. It is therefore quite natural to extend KFVS by splitting the Maxwellian velocity distribution at Boltzmann level based on the sign of the normal component of the relative velocity. The relative velocity is the difference between the molecular velocity (v) and the velocity of the moving surface(w). This inherent simplicity of the Kinetic Flux Vector Splitting scheme on Moving Grids (KFMG) method has prompted us to extend the same ideas to 2-D and 3-D problems leading to the present KFMG method. If w is set to zero then KFMG formulation reduces to the one corresponding to KFVS. Thus KFMG formulations axe generalisation of the KFVS formulation. In 2-D and 3-D cases, in addition to the KFMG formulation, the method to move the grids, the appropriate boundary conditions for treating moving surfaces and techniques to improve accuracy in space and time are required to be developed. The 2-D and 3-D formulations based on Kinetic Flux Vector Splitting scheme on Moving Grids method have been developed for computing unsteady flows. Between two successive time steps, the body changes its orientation in case of an oscillation or it deforms when subjected to, aerodynamic loads. In either of these cases the grid corresponding to the first time step has to be moved or regenerated around the displaced or deformed body. There are several approaches available to generate grids around moving bodies. In the present work, the 'spring analogy method' is followed to obtain grid around deflected geometries within the frame work of structured grid. Using this method, the grids are moved from previous time to the current time. This method is capable of tackling any kind of aeroelastic deformation of the body. For oscillating bodies, a suitable boundary condition enforcing the flow tangency on the body needs to be developed. As a first attempt, the body surface has been treated as an 1-D piston undergoing compression and expansion. Then, a more general Kinetic Moving Boundary Condition(KMBC) has been developed. The KMBC uses specular reflection model of kinetic theory of gases. In order to treat fixed outer boundary, Kinetic Outer Boundary Condition(KOBC) has been applied. The KOBC is more general in the sense that, it can treat different type of boundaries (subsonic, supersonic, inflow or out flow boundary). A 2-D cell-centered finite volume KFMG Euler code to operate on structured grid has been developed. The time accuracy is achieved by incorporating a fourth order Runge-Kutta time marching method. The space accuracy has been enhanced by using high resolution scheme as well as second order scheme using the method of reconstruction of fluxes. First, the KFMG Euler code has been applied to standard test cases for computing steady flows around NACA 0012 and NACA 64AQ06 airfoils in transonic flow. For these two airfoils both computational and experimental results are available in literature. It is thus possible to verify (that is, prove the claim that code is indeed solving the partial differential equations + boundary conditions posed to the code) and validate(that is, comparison with experimental results) the 2-D KFMG Euler code. Having verified and validated the 2-D KFMG Euler code for the standard test cases, the code is then applied to predict unsteady flows around sinusoidally oscillating NACA 0012 and NACA 64A006 airfoils in transonic flow. The computational and experimental unsteady results are available in literature for these airfoils for verification and validation of the present results. The unsteady lift and normal force coefficients have been predicted fairly accurately by all the CFD codes. However there is some difficulty about accurate prediction of unsteady pitching moment coefficient. Even Navier-Stokes code could not predict pitching moment accurately. This issue needs further in depth study and probably intensive computation which have not been undertaken in the present study. Next, a two degrees of £reedom(2-DOF) structural dynamics model of an airfoil undergoing pitch and plunge motions has been coupled with the 2-D KFMG Euler code for numerical simulation of aeroelastic problems. This aeroelastic analysis code is applied to NACA 64A006 airfoil undergoing pitch and plunge motions in transonic flow to obtain aeroelastic response characteristics for a set of structural parameters. For this test case also computed results are available in literature for verification. The response characteristics obtained have showed three modes namely stable, neutrally stable and unstable modes of oscillations. It is interesting to compare the value of airfoil-to-air mass ratio (Formula) obtained by us for neutrally stable condition with similar values obtained by others and some differences between them are worth mentioning here. The values of \i for neutral stability are different for different authors. The differences in values of (Formula) predicted by various authors are primarily due to differences which can be due to grid as well as mathematical model used. For example, the Euler calculations, TSP calculations and full potential calculations always show differences in shock location for the same flow problem. Changes in shock location will cause change in pressure distribution on airfoil which in turn will cause changes in values of \L for conditions of neutral stability. The flutter speed parameter(U*) has also been plotted with free stream Mach number for two different values of airfoil - to - air mass ratio. These curves shown a dip when the free stream Mach number is close to 0.855. This is referred as "Transonic Dip Phenomenon". The shock waves play a dominant role in the mechanism of transonic dip phenomenon. Lastly, cell-centered finite volume KFMG 3-D Euler code has been developed to operate on structured grids. The time accuracy is achieved by incorporating a fourth order Runge-Kutta method. The space accuracy has been enhanced by using high resolution scheme. This code has 3-D grid movement module which is based on spring analogy method. The KMBC to treat oscillating 3-D configuration and KOBC for treating 3-D outer boundary have also been formulated and implemented in the code. The 3-D KFMG Euler code has been first verified and validated for 3-D steady flows around standard shapes such as, transonic flow past a hemisphere cylinder and ONERA M6 wing. This code has also been used for predicting hypersonic flow past blunt cone-eylinder-flare configuration for which experimental data are available. Also, for this case, the results are compared with a similar Euler code. Then the KFMG Euler code has been used for predicting steady flow around ogive-cylinder-ogive configuration with elliptical cross section. The aerodynamic coefficients obtained have been compared with those of another Euler code. Thus, the 3-D KFMG Euler code has been verified and validated extensively for steady flow problems. Finally, the 3-D KFMG based Euler code has been applied to an oscillating ogive-cylinder-ogive configuration in transonic flow. This test case has been chosen as it resembles the core body of a flight vehicle configuration of interest to DRDO,India. For this test case, the unsteady lift coefficients are available in literature for verifying the present results. Two grid sizes are used to perform the unsteady calculations using the present KFMG 3-D Euler code. The hysteresis loops of lift and moment coefficients confirmed the unsteady behaviour during the oscillation of the configuration. This has proved that, the 3-D formulations are capable of predicting the unsteady flows satisfactorily. The unsteady results obtained for a grid with size of 45x41x51 which is very close to the grid size chosen in the reference(Nixon et al.) are considered for comparison. It has been mentioned in the reference that, a phase lag of (Formula) was observed in lift coefficients with respect to motion of the configuration for a free stream Mach number of 0.3 with other conditions remaining the same. The unsteady lift coefficients obtained using KFMG code as well as those available in literature are plotted for the same flow conditions. Approximately the same phase lag of (Formula) is present (for (Formula)) between the lift coefficient curves of KFMG and due to Nixon et al. The phase lag corrected plot of lift coefficient obtained by Nixon et al. is compared with the lift coefficient versus time obtained by 3-D KFMG Euler code. The two results compare well except that the peaks are over predicted by KFMG code. It is nut clear at this stage whether our results should at all match with those due to Nixon et al. Further in depth study is obviously required to settle the issue. Thus the Kinetic Flux Vector Splitting on Moving Grids has been found to be a very good and a sound method for splitting fluxes and is a generalisation of earlier KFVS on fixed grids. It has been found to be very successful in numerical simulation of unsteady aerodynamics and computational aeroelasticity.

Technological improvements on wind energy systems with governmental supports have increased the penetration level of wind power into the grid in recent years. The high level of penetration forces the wind turbines stay connected to the grid during the disturbances in order to enhance system stability. Moreover, power system operators must revise their grid codes in parallel with these developments. This work is devoted to the modeling of variable speed wind turbines and the investigation of fault ride trough capability of the wind turbines for grid integration studies. In the thesis, detailed models of different variable speed wind turbines will be presented. Requirements of grid codes for wind power integration will also be discussed regarding active power control, reactive power control and fault ride through (FRT) capability. Investigation of the wind turbine FRT capability is the main focus of this thesis. Methods to overcome this problem for different types of wind turbines will be also explained in detail. Models of grid-connected wind turbines with doubly-fed induction generator and permanent magnet synchronous generator are implemented in the dedicated power system analysis tool PSCAD/EMTDC. With these models and computer simulations, FRT capabilities ofvariable speed wind turbines have been studied and benchmarked and the influences on the grid during the faults are discussed.

In this thesis we describe the development of Reynolds- averaged Navier Stokes code for the flow past two- dimensional configuration. Particularly, emphasis has been laid on the study of low Reynolds number airfoil aerodynamics. The thesis consists of five chapters covering the back ground history, problem formulation, method of solution and discussion of the results and conclusion. Chapter I deals with a detailed background history of low Reynolds number aerodynamics, problem associated with it, state of the art, its importance in practical applications in aircraft industries. Chapter II describes the mathematical model of the flow physics and various levels of approximations. Also it gives an account of complexity of the equations at low Reynolds number regarding flow separation, transition and reattachment. Chapter III describes method of solution, numerical algorithm developed, description of various upwind schemes, grid system, finite volume discrieti-zation of the governing equations described in Chapter II. Chapter IV describes the application of the newly developed Navier Stokes code for the test cases from GAMM Workshop proceedings. Also it describes validation of the code for Euler solutions, Blasius solution for the flow past flat plate and compressible Navier Stokes solution for the flow past NACA 0012 Airfoil at low Reynolds number. Chapter V describes the application of the Navier Stokes code for the more test cases of current practical interest . In this chapter laminar separation bubble characteristics are investigated in detail regarding formation, growth and shedding in an unsteady environment. Finally the conclusion is drawn regarding the robustness of the newly developed code in predicting the airfoil aerodynamic characteristics at low Reynolds number both in steady and unsteady environment. Lastly, suggestion for future work has been highlighted.

Општи информациони модел (CIM) користи се за опис електроенергетске мреже и за размену података између оператера преносних електроенергетских система. Како је модел постајао све заступљенији, појавила се потреба за његовим складиштењем. У раду је развијен методолошки приступ за развој базе података која би подржала релативно једноставно складиштење и рад са инстанцама CIM модела, које описују тренутно, активно стање у систему. Такође, омогућено је и праћење претходних, историјских стања CIM инстанци, као и њихова рестаурација у жељено стање. Очекује се да предложени приступ олакша увођење CIM модела у различита, наменска програмска решења.
Opšti informacioni model (CIM) koristi se za opis elektroenergetske mreže i za razmenu podataka između operatera prenosnih elektroenergetskih sistema. Kako je model postajao sve zastupljeniji, pojavila se potreba za njegovim skladištenjem. U radu je razvijen metodološki pristup za razvoj baze podataka koja bi podržala relativno jednostavno skladištenje i rad sa instancama CIM modela, koje opisuju trenutno, aktivno stanje u sistemu. Takođe, omogućeno je i praćenje prethodnih, istorijskih stanja CIM instanci, kao i njihova restauracija u željeno stanje. Očekuje se da predloženi pristup olakša uvođenje CIM modela u različita, namenska programska rešenja.
Common Information Model (CIM) is used for describing power grid networksand data exchange among transmission system operators (TSO). As themodel became widely used, there was a need to store such model. In thisthesis we present a methodological approach to development of a databasethat supports relatively easy storing and managing CIM instances, whichdescribe current, active state of the system. Also, tracking changes andrestoring CIM instances to its previous states are supported. We expect thatsuch methodological approach would ease the implementation of CIM modelin various, domain specific software solutions.

The use of the insulated concrete form (ICF) walls in residential buildings has increased over the past few decades. Much research has been conducted to evaluate the lateral strength of these walls by applying monotonic and cyclic loadings. In the current study, full-scale shake table experiments were employed to evaluate the in-plane behavior of four screen grid insulated concrete form (SGICF) walls. The first two wall specimens utilized dry fit insulated form blocks made from recycled expanded polystyrene granules that were bonded together with cement. When stacked, the cavities in the blocks formed a grid of cores that are evenly spaced vertically and horizontally. The walls consisted of four circular vertical cores and five circular horizontal cores reinforced with a single rebar placed nominally in the center of each core. The rest of the wall specimens were newly suggested pattern of SGICF walls, which consisted of three circular vertical cores and five circular horizontal cores. Two rebars were placed in each vertical core, and a single rebar was placed nominally in the center of each horizontal core. Each wall was built on top of a foundation block that was designed such that failure would occur within the walls themselves. For each type of SGICF walls, steel fiber-reinforced concrete was used in one of the walls to evaluate the effect on failure modes, drift capacity, and shear strength. The results showed that the use of fiber-reinforced concrete in the cores of the SGICF walls that were built out of ICF blocks had not significantly improved the drift capacity, and had exhibited lower strengths than the wall with conventional concrete. These outcomes were mainly attributed to voids in the cores that had resulted despite similarities in workability of the concrete mixes and in techniques used to place the concrete in the walls. On the other hand, the use of the steel fiber-reinforced concrete in the cores of the newly suggested pattern of SGICF wall and the two rebars in the vertical cores had improved the drift ductility of the wall by about 63%. The evaluation of the steel fiber-concrete was conducted at the component levels of the SGICF walls. Six simply supported reinforced concrete beams (3 ft. long) were tested in a three-point bending configuration by applying a cyclic loading protocol. Results showed that the steel fiber-concrete did not improve the lateral strength and the drift capacity. Steel fiber dose played an essential role in this investigation. Analytical approaches were used to estimate the initial stiffness and the lateral strength of the SGICF walls. None of the approaches managed to provide an acceptable estimation of the initial stiffness. Meanwhile, the summation of individual vertical core plastic moment capacity and the ACI equation for the minimum shear strength of the concrete methods were successful in estimating the in-plane lateral strengths. Finally, a computer model was created to predict the lateral in-plane behavior of the SGICF walls. Results showed that the computer model provided good estimations for the peak lateral strength and the initial stiffness.

The installation of wind power plant has significantly increased since several years due to the recent necessity of creating renewable and clean energy sources. Before the accomplishment of a wind power project many pre-studies are required in order to verify the possibility of integrating a wind power plant in the electrical network. The creation of models in different software and their simulation can bring the insurance of a secure operation that meets the numerous requirements imposed by the electrical system. Hence, this Master thesis work consists in the creation of a wind turbine model. This model represents the turbines installed at Lillgrund wind farm, the biggest wind power plant in Sweden. The objectives of this project are to first develop an accurate model of the wind turbines installed at Lillgrund wind farm and further to use it in different kinds of simulations. Those simulations test the wind turbine operating according to different control modes. Also, a power quality analysis is carried out studying in particular two power quality phenomena, namely, the response to voltage sags and the harmonic distortion. The model is created in the software PSCAD that enables the dynamic and static simulations of electromagnetic and electromechanical systems. The model of the wind turbine contains the electrical machine, the power electronics (converters), and the controls of the wind turbine. Especially, three different control modes, e.g., voltage control, reactive power control and power factor control, are implemented, tested and compared. The model is tested according to different cases of voltage sag and the study verifies the fault-ride through capability of the turbine. Moreover, a harmonics analysis is done. Eventually the work concludes about two power quality parameters.

Ce manuscrit traite de la fiabilisation des CPL-BE dans le contexte smart grid avec l’application des techniques de codage correcteur d’erreurs et d’effacements. Après une introduction sur le concept de smart grid, le canal CPL-BE est caractérisé précisément et les modèles qui le décrivent sont présentés. Les performances des codes à métrique rang, simples ou concaténés avec des codes convolutifs, particulièrement intéressants pour combattre le bruit criss-cross sur les réseaux CPL-BE sont simulées et comparées aux performances des codes Reed-Solomon déjà présents dans plusieurs standards. Les codes fontaines qui s’adaptent à n’importe quelles statistiques d’effacements sur le canal CPL sont utilisés et les performances de schémas coopératifs basés sur ces codes fontaines sur des réseaux linéaires multi-sauts sont étudiés. Enfin des algorithmes permettant de combiner le codage réseau et le codage fontaine pour la topologie particulière des réseaux CPL pour les smart grid sont proposés et évalués
This PhD dissertation deals with the mitigation of the impact of the Narrowband PowerLine communication (NB-PLC) channel impairments e.g., periodic impulsive noise and narrowband noise, by applying the error/erasure correction coding techniques. After an introduction to the concept of smart grid, the NB-PLC channels are characterized precisely and models that describe these channels are presented. The performance of rank metric codes, simple or concatenated with convolutional codes, that are particularly interesting to combat criss-cross errors on the NB-PLC networks are simulated and compared with Reed- Solomon (already present in several NB-PLC standards) codes performance. Fountain codes that can adapt to any channel erasures statistics are used for the NB-PLC networks and the performance of cooperative schemes based on these fountain codes on linear multi-hop networks are studied. Finally, algorithms to combine the network coding and fountain codes for the particular topology of PLC networks for the smart grid are proposed and evaluated

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-04-18T18:59:28Z No. of bitstreams: 1 Leonardodemellobrandaoabdodib.pdf: 1435361 bytes, checksum: 5e9afeb4cc3aff2697cb2afe973ab9ca (MD5)
Rejected by Adriana Oliveira (adriana.oliveira@ufjf.edu.br), reason: on 2018-04-19T13:20:42Z (GMT)
Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-04-19T13:31:11Z No. of bitstreams: 1 leonardodemellobrandaoabdodib.pdf: 1435361 bytes, checksum: 5e9afeb4cc3aff2697cb2afe973ab9ca (MD5)
Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-04-19T13:32:56Z (GMT) No. of bitstreams: 1 leonardodemellobrandaoabdodib.pdf: 1435361 bytes, checksum: 5e9afeb4cc3aff2697cb2afe973ab9ca (MD5)
Made available in DSpace on 2018-04-19T13:32:56Z (GMT). No. of bitstreams: 1 leonardodemellobrandaoabdodib.pdf: 1435361 bytes, checksum: 5e9afeb4cc3aff2697cb2afe973ab9ca (MD5) Previous issue date: 2018-02-28
Este trabalho descreve características importantes de um sistema híbrido power line communication (PLC)/comunicação sem fio para aplicações smart grid (SG) e Internet das coisas (IoT). Além disso, discute as vantagens dos sistemas híbridos em comparação com os sistemas não híbridos. Estas vantagens são demonstradas não somente do ponto de vista técnico, mas também pela perspectiva de infraestrutura. Além disso, esta dissertação destaca uma conexão entre a capilaridade do IoT e a infraestrutura de comunicação fornecida pelo SG, bem como os aspectos de segurança que relacionam o contexto SG e IoT. Além disso, este trabalho aborda a influência do meio ambiente nas comunicações de rede elétrica e sem fio. Por outro lado, existe um enorme esforço de pesquisa em relação às tecnologias avançadas de comunicação de dados, considerando tanto as aplicações IoT de baixa taxa de bits quanto as aplicações SG, de modo a cumprir os requisitos de projeto para sistemas de telecomunicações. Com o objetivo de maximizar o uso da largura de banda disponível para aplicações PLC, esta dissertação faz uso do esquema orthogonal chirp division multiplexing (OCDM) que usa a transformada discreta de Fresnel de forma análoga à transformada discreta de Fourier. Trabalhos anteriores mostraram resultados de desempenho interessantes para esse esquema em aplicações de banda passante (por exemplo, comunicação sem fio, fibra óptica e mídia acústica subaquática). Este trabalho aborda a construção de versões do esquema OCDM que permitem a comunicação de dados usando sinais banda base, possibilitando a aplicação do esquema OCDM em sistemas PLC. Além disso, ele introduz um esquema baseado em vários usuários denominado multichirp code division multiple access (MCp-CDMA), que é uma combinação de CDMA e OCDM com o objetivo de acomodar um grande número de nós e endpoints para PLC de banda estreita e que também seja adequado para aplicações SG e IoT. Finalmente, os resultados numéricos apontam que, para um ambiente difícil e ruidoso, o esquema OCDM é capaz de suavizar o efeito do ruído impulsivo. Além disso, o esquema OCDM demonstrou resultados excepcionais quando o comprimento do canal é desconhecido comparativamente aos esquemas Hermitian symmetric orthogonal frequency division multiplexing e monoportadora com prefixo cíclico. As simulações usando o esquema MCp-CDMA demonstraram grande estabilidade e consistência de desempenho entre os diferentes cenários analisados.
This work outlines important characteristics of hybrid power line communication (PLC)/wireless data communication system for smart grid (SG) and Internet of Things (IoT) applications. Moreover, it discusses the hybrid systems advantages in comparison to non-hybrid ones. These advantages are demonstrated not only in the technical point of view but also in the infrastructural perspective. Also, this thesis highlights a connec-tion between the capillarity of IoT and the communication infrastructure provided by SG as well as the security aspects that relate SG and IoT context. Furthermore, this work addresses the environmental influence on wireless and power line communications. In another hand, there is a huge research effort regarding advanced data communication technologies considering both low bit rate IoT and SG applications in order to comply with the requirements to design telecommunications systems. Aiming to maximize the use of the available bandwidth for PLC applications, this thesis makes use of the orthog-onal chirp division multiplexing (OCDM) scheme that uses discrete Fresnel transform in an analogous fashion as discrete Fourier transform. Previous works showed interesting performance results for such scheme in passband applications (e.g., wireless, optical fiber, and underwater acoustic media). This work addresses the design of versions of the OCDM scheme that can allow the data communication using baseband signals, making possible the application of the OCDM scheme in PLC systems. Furthermore, it introduces a mul-tiuser based scheme termed multichirp code division multiple access (MCp-CDMA), which is a combination of CDMA and OCDM, in order to accommodate a large number of nodes and end-points aiming narrowband PLC that is also suitable for SG and IoT applications. Finally, numerical results point out that for a hard and noisy environment, OCDM scheme is able to soften the impulsive noise effect. Also, OCDM scheme demonstrated outstand-ing results when the channel length is unknown comparatively to Hermitian symmetric orthogonal frequency division multiplexing and single carrier-cyclic prefix schemes. The simulations using the MCp-CDMA scheme demonstrated great stability and performance consistency among the different scenarios analyzed.

The ever demanding bandwidth requirements for supporting emerging telecom services such as ultra-high-definition video streaming, cloud computing, connected car, virtual/augmented reality, etc., bring to the fore the necessity to upgrade continuously the technology behind transport networks in order to keep pace with this exponential traffic growth. Thus, everything seems to indicate that fixed-grid Wavelength-Division Multiplexed (WDM) networks will be upgraded by adopting a flexible-grid, thus providing finer bandwidth allocation granularities, and therefore, increasing the Grade-of-Service by packing more information in the same spectral band of standard Single-Mode Fibers (SMFs). Nevertheless, unfortunately, the fundamental Shannon’s limit of SMFs is rapidly approaching, and, then, the research efforts to increase the SMFs' capacity will be useless. One solution to overcome this capacity crunch effect is to enable one extra dimension in addition to the frequency one, namely, the spatial dimension, thus deploying S parallel paths in order to multiply, in the best case, by S the capacity of SMF-based networks. However, additionally, it is necessary to decrease the cost and energy per bit in order to provide economically attractive solutions. For this purpose, a smooth upgrade path has to be carried out as new integrated devices and system components are developed for Space Division Multiplexing (SDM). This thesis is concentrated on the planning and operation of the combined flexible WDM and SDM networks (i.e., Flex-Grid/SDM networks) proposing several strategies aimed at optimizing network resources usage with hardware complexity analysis. For this purpose, firstly, network problems are carefully studied and stated, and then, mathematical and/or heuristic algorithms are designed and implemented in an optical network simulator. Specifically, after an introduction to the thesis, chapter 2 presents the background and related work. Next, chapter 3 concentrates on the study of spatially fixed Flex-Grid/SDM networks, i.e., when a rigid number of spatial channels are reserved per allocated traffic demand. In its turn, chapter 4 studies the case of Spectrally-Spatially Flexible Optical Networks (SS-FONs), as the ones providing the upper-bound network capacity. Costs and hardware requirements implied on providing this flexibility are analyzed. Network nodes aimed at reducing the cost of SS-FONs are presented and evaluated in chapter 5. Finally, this thesis ends with the presentation of the main contributions and future research work in chapter 6.
La demanda de ancho de banda cada vez más exigente para soportar servicios de telecomunicación emergentes tales como la transmisión de video de alta calidad, computación en la nube, vehículo conectado, realidad virtual/aumentada, etc.…, ha puesto de manifiesto la necesidad de actualizar constantemente la tecnología detrás de las redes de transporte óptico con la finalidad de ir a la par de este incremento exponencial del tráfico. De esta manera, todo parece indicar que las redes basadas en la multiplexación por division de longitud de onda (Wavelength Division Multiplexing, WDM) de ancho espectral fijo serán actualizadas adoptando un ancho de banda espectral flexible, que ofrece asignaciones de ancho de banda con granularidad más fina acorde a las demandas de tráfico; y por lo tanto, incremanta el Grado de Servicio de la red, ya que se permite acomodar mayor información en la misma banda espectral de las fibras monomodo (Single Mode Fibers, SMFs). Sin embargo, desafortunadamente, el límite de Shannon de las fibras monomodo se está aproximando cada vez más, y cuando esto ocurra las investigaciones para incrementar la capacidad de las fibras monomodo serán infructuosas. Una posible solución para superar este colapso de las fibras monomodo es habilitar la dimensión espacial a más de la frecuencial, desplegando 𝑆� caminos paralelos con la finalidad de multiplicar por 𝑆� (en el mejor de los casos) la capacidad de las fibras monomodo. No obstante, es necesario disminuir el costo y la energía por bit con la finalidad de proveer soluciones comerciales atractivas. Para tal propósito debe llevarse a cabo una actualización moderada conforme nuevos dispositivos y componentes integrados son desarrollados para la implementación de la tecnología basada en la multiplexación por división de espacio (Space Division Multiplexing, SDM). Esta tesis se concentra en la planificación y operación de la combinación de las redes WDM flexibles y SDM (es decir, de las redes Flex-Grid/SDM) proponiendo varias estrategias dirigidas a optimizar el uso de los recursos de red junto con el análisis de la complejidad del hardware que viene acompañada. Para este fin, primeramente, los problemas de red son cuidadosamente estudiados y descritos. A continuación, se han diseñado e implementado algoritmos basados en programación lineal entera o heurísticas en un simulador de redes ópticas. Después de una introducción inicial, el capítulo 2 de esta tesis presenta el marco teórico sobre los conceptos tratados y los trabajos publicados anteriormente. A continuación, el capítulo 3 se concentra en el estudio de las redes Flex-Grid/SDM con la dimensión espacial rígida; es decir, cuando un número fijo de canales espaciales son reservados por cada demanda de tráfico establecida. Por su parte, el capítulo 4 estudia las redes Flex-Grid/SDM considerando flexibilidad tanto en el dominio espacial como espectral (Spectrally and Spatially Flexible Optical Networks, SS-FONs), las cuales proveerían la capacidad máxima de las redes SDM. Adicionalmente, los costos y requerimientos de hardware implicados en la provisión de esta flexibilidad son analizados. El capítulo 5 presenta la evaluación de nodos orientados a reducir los costos de las SS-FONs. Finalmente, el capítulo 6 expone las principales contribuciones y las posibles líneas de trabajo futuro
Els requisits incessants d’ample de banda per al suport de nous serveis de telecomunicació, com poden ser la difusió en directe de vídeo de molt alta definició, la informàtica en el núvol, els cotxes intel·ligents connectats a la xarxa, la realitat virtual/augmentada, etc…, han exigit una millora contínua de les tecnologíes de les actuals xarxes de transport de dades. Tot sembla indicar que les xarxes de transport òptiques actuals, basades en la tecnologia de multiplexació per divisió de longitud d’ona (Wavelength Division Multiplexing, WDM) sobre un grid espectral rígid, hauran de ser reemplaçades per tecnologies òptiques més flexibles, amb una granularitat més fina a l’hora de suportar noves connexions, incrementat el grau de servei de les xarxes gràcies a aprofitament major de l’ample de banda espectral proporcionat per les fibres òptiques monomode (Single Mode Fibers, SMFs). Tanmateix, estem exhaurint ja la capacitat màxima de les fibres òptiques SMF segons ens indica el límit fonamental de Shannon. Per tant, qualsevol esforç enfocat a millorar la capacitat d’aquestes xarxes basades en SMFs pot acabar sent infructuós. Una possible solució per superar aquestes limitacions de capacitat és explorar la dimensió espacial, a més de l’espectral, desplegant 𝑆 camins en paral·lel per tal de multiplicar per 𝑆, en el millor cas, la capacitat de les SMFs. Tot i això, és necessari reduir el cost i el consum energètic per bit transmès, per tal de proporcionar solucions econòmicament viables. Amb aquest propòsit, pot ser necessària una migració progressiva, a mesura que es desenvolupen nous dispositius i components per aquesta nova tecnologia de multiplexació per divisió espacial (Spatial Division Multiplexing, SDM). La present tesi es centra en la planificació i operació de xarxes òptiques de nova generació que combinin tecnologies de xarxa WDM flexible i SDM (és a dir, xarxes Flex-Grid/SDM), proposant estratègies per a l’optimització de l’ús dels recursos de xarxa i, en definitiva, el seu cost (CapEx). Amb aquest propòsit, s’analitzen en primer moment els problemes adreçats. Tot seguit, es dissenyen algorismes per tal de solucionar-los, basats en tècniques de programació matemàtica i heurístiques, els quals s’implementen i es proven en un simulador de xarxa òptica. Després d’una introducció inicial, el capítol 2 d’aquesta tesi presenta tots els conceptes tractats i treballs relacionats publicats amb anterioritat. Tot seguit, el capítol 3 es centra en l’estudi de les xarxes Flex-Grid/SDM fixes en el domini espai, és a dir, on sempre es reserva un nombre rígid de canals espacials per qualsevol demanda suportada. El capítol 4 estudia les xarxes flexibles en els dominis espectrals i espacials (Spectrally-Spatially Flexible Optical Nextworks, SS-FONs), com aquelles que poden proporcionar una capacitat de xarxa màxima. En aquest context, s’analitzen els requeriments en termes de cost i hardware per tal de proporcionar aquesta flexibilitat. Llavors, en el capítol 6 es presenten opcions de node de xarxa capaces de reduir els costos de les xarxes SS-FONs. Finalment, en el capítol 7 es repassen totes les contribucions de la tesi, així com posibles línies de treball futur

Many AC grids suffer from decreased frequency stability due to less system inertia. This has increased the risk of large-scale blackouts. This thesis and its papers address the frequency stability problem from a hydropower perspective. Grid frequency stability assessments often require accurate system inertia estimates. One approach is to estimate the inertia of all individual power plants and sum up the results. We implemented three inertia estimation methods on a Kaplan unit and compared their results. The generator contributed with 92-96% of the unit inertia, which verified the results from previous studies. However, the three methods estimated slightly different values for the unit inertia, which raises the question of when to use which method. Hydropower often deliver frequency control, yet we found no studies which validate Kaplan turbine models for large grid frequency disturbances on strong grids. Therefore, we performed frequency control tests on a Kaplan unit, implemented three hydropower models, and compared the simulation results to the measurement data. The models overestimated the change in output power and energy delivered within the first few seconds after a large change in frequency. Thus, it is important to have sufficient stability margin when using these types of hydropower models to assess the grid frequency stability. The Nordic transmission system operators are updating their frequency control requirements. We used measurement data and simulation models to assess whether improved runner blade angle control could help a Kaplan unit fulfill the coming requirements. The results showed that improved runner control does not improve the performance sufficiently for requirements fulfillment. The requirements are based on an assumption on minimum system inertia and became easier to fulfill if they were implemented with more system inertia. Thus, more inertia could allow more participants to deliver frequency control in the Nordic grid.

Responsive design is a common expression at the web today. This thesis was about learning about responsive web design in order to apply it to Windows 8 applications created in C# and XAML. The purpose of this thesis was to learn if responsive design can be used in such applications. This was done by first learning about responsive design through a literature study about responsive web design and then specifying responsive application design. How responsive design can be used in applications was found through research and creation of an example application. No literature was found about responsive design for Windows 8 applications in C# and XAML and therefore most of the results came from own ideas and partly solutions found on different forums. The thesis was performed at Infor in Kista. The example application was a social application which was connected to a social web service developed by Infor. Responsive web design is a technique used for making webpages adapt to the size and resolution of the viewport. This is done by creating a structured, fluid layout by using a flexible grid and flexible images. Media queries are used to set up different states for presenting the page in different ways for different sizes and resolutions of the viewport. In the different states parts of the content can for example be hidden or styled. The number of columns of information can also be set to adapt to make the page easier to view. Responsive design for applications should make the layout of the application adapt to fit the application window of the device used depending on its resolution. One way to specify a responsive design for Windows 8 applications could be to create only one application which could be used on all different Windows 8 platforms, such as phones, tablets and computers. It is probably not possible today to create this one application for different Windows 8 platforms. Another way of specifying responsive design for application is to create a responsive user interface which could be shared and used in the different Windows 8 applications. The latter was the chosen definition for this thesis. The scope of this thesis was limited to only research for responsive design in Windows Store apps and Windows Phone 8 applications. Windows Phone 8 applications are applications used on smartphones with Windows Phone 8 as operating system while Windows Store applications are used on computers with Windows 8 as operating system. Other Windows 8 devices were not included in this thesis. The final conclusion of this thesis was that although it is complicated to use responsive application design it can be used for most of the user interface. A responsive user interface for the applications can be created separately, but some parts of the application pages cannot be shared between the different platforms. This results in a mostly responsive sharable user interface.

According to the International Energy Agency 2016 statistics, Ethiopia is among the lowest countries in annual electricity consumption, 70 KWh/capita. Rural areas hold more than 80% of the country’s population and less than 30% of them have been electrified. Most of the population (the rural areas) still predominantly depend on traditional biomass energy sources for cooking and heating, and household lights are provided mainly by kerosene and biomass including this study area, Tadacha Rarasa, which consist of 4100 households with 6 members, totally 24,600 people[1, 2]. The feasibility study of hybrid system consisting of small Hydro, PV, Wind and Battery is carried out using HOMER as a tool for optimization and sensitivity analysis. TURBNPRO software also assists for the optimization of the small hydropower which is suggested to utilize the 2.2 m3/s ecological flow of the Genale 3 multipurpose hydropower plant’s reservoir. The wind speed and solar radiation data of the site is collected from NASA. Then, the wind speed, solar radiation, electric load and hydro data is input to HOMER in their respective appropriate format for simulation and analysis of the proposed hybrid system.  Electric loads of the community is estimated bearing in mind the irrigation, fishery and other opportunities which will arise after the multipurpose project completion in addition to basic household demands. The daily average estimated residential consumption by each family is 9.118 kWh and the daily average total energy consumption per person is 1.872 kWh.   After optimization and sensitivity analysis using HOMER, several different feasible configurations of Hydro, PV, Wind and Battery hybrid system has been displayed with a range of 0.049 to 0.067 $/kWh cost of energy. The optimum configuration becomes Hydro/PV/Battery hybrid system with 0.049 $/kWh levelized COE which is closer to the national energy tariff, 0.032 USD/kWh. The optimum Hydro/PV/Battery hybrid system generates annually 18,647,372 kWh with 0.18% capacity shortage and 0.15% unmet load. The hydropower supports the base load and the PV supplies for the peak load demand in the daytime which shares 19% of the total electric production.

The EU has concluded that it needs a fully functioning and integrated internal electricity market to face the challenges of integrating renewable energy sources into the electricity grid. The European Commission has created guidelines for what the legislation is supposed to contain to create such a market. The so called grid codes are today around ten codes which successively are being implemented in national legislation for all member states. They regard connection-, marketand operation of the electricity grid and consists of several legal requirements for all member states. This study is divided in three parts. In the first part challenges with more renewable energy sources are described and the technical strategies that are suitable to solve those challenges. The second part describes an analysis of the connection- and operational codes on behalf of Ellevio, a distribution system operator in Sweden. They are interested in how the new legislation will affect their work and which new costs that will appear. The third part contains an overall study about the German electricity system since they have a lot of renewable energy sources in their production. The purpose was to see how they have handled challenges within their grid and their view on the new legislation. The overall result in this study was that the grid codes will change the role for Ellevio, which in the following years will have to handle higher information flow between grid users and Svenska kraftnät, which is the transmission system operator in Sweden. An another result was that the technical strategies are included in the legal requirements of the codes and that the legal requirements have been influenced to a great extent by the current German legislation.

Atualmente, a energia eólica é uma das fontes renováveis mais reconhecidas, e sua penetração em sistemas elétricos de potência está se incrementando consideravelmente. Por consequência, a participação de turbinas eólicas em sistemas elétricos de potência tem se incrementado e pode influenciar o comportamento geral do sistema de potência. Portanto, é importante estudar o desempenho de turbinas eólicas em sistemas elétricos e sua interação com outros equipamentos de geração e cargas. O principal objetivo nesta dissertação é determinar o desempenho dinâmico de diferentes tecnologias ligadas nos sistemas elétricos considerando diferentes níveis de penetração e diferentes perturbações elétricas mediante simulações realizadas usando um toolbox de Matlab/Simulink, SimPowerSystems. As tecnologias avaliadas são (a) o gerador de indução duplamente alimentado com fator de potência unitário, (b) o gerador de indução duplamente alimentado com controle de tensão, (c) o gerador de indução de gaiola de esquilo com compensação baseada em condensadores, e (d) gerador de indução de gaiola de esquilo sem equipamentos auxiliares. Os fatores técnicos analisados são perfil de tensão em estado estacionário, as dinâmicas durante afundamentos e elevações de tensão, correntes de curto circuito, e incremento gradual nas cargas do sistema, para verificar a estabilidade de tensão da rede para pequenas perturbações. É proposta uma estratégia para promover uma integração efetiva de turbinas eólicas em sistemas de potência com altos níveis de penetração considerando diferentes normas de operação da rede para sistemas de transmissão e de distribuição. O objetivo nesta estratégia é o cumprimento dos requisitos para conexão de rede com a combinação de tecnologias, minimizando o valor do investimento. Os efeitos na estabilidade de sistemas de potência da fazenda eólica determinada com a metodologia proposta são comparados com os efeitos de uma fazenda eólica de igual capacidade de energia eólica considerando somente geradores de indução duplamente alimentados com controle de tensão. Para as analises realizadas neste trabalho são considerados os sistemas IEEE de 9 e 30 barras.
Nowadays, wind power is one of the most accepted renewable energy sources, and its penetration in electrical power systems is increasing considerably. Consequently, the participation of wind turbines in electrical power systems has increased and may influence the overall power system behavior. It is therefore important to study the performance of wind turbines in electrical power systems and their interaction with other generation equipment and loads. The main objective of this dissertation is to determine the dynamic performance of different wind turbines technologies connected in electrical system considering different penetration levels and electrical perturbations by simulations performed using a Matlab/Simulink toolbox, SimPowerSystems. The assessed technologies are (a) double fed induction generator with unity power factor, (b) double fed induction generator with voltage control, (c) squirrel cage induction generator with capacitor-based compensation, and (d) squirrel cage induction generator without ancillary devices. The technical factors analyzed are steady-state voltage profile, the dynamics during voltage sags and swells, short-circuit currents, and gradual increase in the system loading, in order to check the network small-disturbance voltage stability. A strategy to promote an effective integration of wind turbines into the power systems with high levels of wind power penetration regarding different grid code requirements in transmission and distribution networks is proposed. The objective in this strategy is fulfilling the grid code requirements with a technology combination, minimizing the invested value. The effects on power system stability of the wind farm, found by the proposed methodology, are compared with the effects that have the same installed capacity of wind power but only considering double fed induction generators with voltage control. The IEEE 9 bus transmission system and the IEEE 30 bus system are regarded for the analysis performed in this work.

Bakgrund: Bålstabilitet är nödvändigt för att hålla balansen och möjliggör kraftöverföring genom kroppen. Detta gör bålstabilitet viktigt i vardagliga sysslor, sportutföranden och för att minska risken för skada. En bättre förståelse över bålstabiliteten i olika sporter kan utveckla träningsprogram, inte bara för att förbättra bålstabiliteten, utan även för att förbättra den generella prestationen. Syfte: Syftet med denna studie var att undersöka skillnader i båluthållighet mellan unga kvinnliga ryttare och fotbollsspelare, och associationen med handgrepp styrka och rotationsrörlighet i ryggen. Metod:  Båluthålligheten undersöktes med McGill’s båluthållighets test, mellan kvinnliga ryttare (n = 10) och fotbollsspelare (n = 10), ålder 16 – 20. Handgreppsstyrkan undersöktes med en handdynamometer och användes som en indikation av generell styrka. Ryggrotations testet undersöktes men en Myrinmätare. Shapiro-Wilks användes för att bekräfta normalfördelning av data. Oberoende t-test användes för att jämföra båluthållighet (sek.) mellan ryttarna och fotbollsspelarna. Signifikansnivån fastställdes till <0,05. Ett styrkeförhållande räknades ut (kg/kg kroppsvikt) och Pearsons korrelationskoefficient användes sedan för att undersöka associationen med båluthållighet (sek.). Pearsons korrelationskoefficient användes också för att undersöka associationen mellan medelvärdet av ryggrotation (°) och båluthållighet (sek.). Hög korrelation fastställdes när r> (0,7), måttlig korrelation när r = (0,3 – 0,7) och låg korrelation när r <0,3.  Resultat: Resultaten visade att ryttarna hade bättre uthållighet i bålextensionen, jämfört med fotbollsspelarna (p = 0,006). Lateralflexionen av bålen visade ingen skillnad mellan ryttarna och fotbollsspelarna (p = 0,924; p = 0,423). Handgrepp styrkan visade måttlig korrelation med bålextensionen (r = 0,631; r² = 0,398) och båda sidor av lateralflexionen av bålen (r = 0,411; r² = 0,169; r = 0,615; r² = 0,378). Rotationsrörligheten i ryggen visade låg korrelation med samtliga båluthållighets tester (r >0,3). Slutsats: Resultaten indikerar få skillnader mellan ryttare och fotbollsspelare, vilket inte är tillräckligt för att fastställa någon slutsats. Korrelationen mellan handgreppsstyrkan och båluthållighet indikerar att bättre bålstabilitet associerar med mer generell styrka.
Background: Core stability is necessary to keep balance and enables force to be transmitted through the body. This makes core stability important in everyday chores, sport performance and to reduce risk of injuries. A better understanding of the core stability in different sports can develop athletes training programs, not only to improve the core stability itself, but also to improve overall performance. Aim: The aim of this study was to examine the differences in core endurance between young female horseback riders and soccer players, and the core endurance association with hand grip strength and spinal rotation mobility. Methods: The McGill’s core endurance test was used to examine the core endurance between female horseback riders (n = 10) and soccer players (n = 10), age 16-20. The hand grip strength was examined with a hand grip dynamometer and was used to get an indication of overall body strength. The spinal rotation mobility was examined with a Myrin goniometer. Shapiro-Wilks was used to confirm the normality of the data. Independent sample t-test was used to compare core endurance time (sec.) between the horseback riders and the soccer players. The significant level was set at < 0.05. A strength ratio was calculated (kg/kg body weight), and the Pearson’s correlation coefficient was used for examining the association to core endurance (sec.). Pearson’s correlation coefficient was also used to examine the association between the spinal rotation mobility (°) and core endurance (sec.). High correlations were set at r > (0.7), moderate when r = (0.3- 0.7) and low when r < (0.3). Results: The result showed that horseback riders had better endurance in the trunk extensor test than the soccer players (p = 0.006). Hand grip strength showed moderate correlation with the endurance time of the trunk extensor test (r = 0.631, r² = 0.398), and with the lateral flexor tests (r = 0.411, r² = 0.169; r = 0.615, r² = 0.378). Low correlation was shown with the trunk flexor test (r = 0.197, r² = 0.039). The spinal rotation mobility test showed low correlation with all the core endurance tests (r >0.3). Conclusion: The results indicates few differences between the horseback riders and the soccer players, which is not enough to draw a conclusion. The correlation between hand grip strength and the core endurance tests indicates that a better core stability might be associated to an increased overall body strength.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
O problema do cÃdigo de identificaÃÃo foi introduzido em 1998 por Karpovsky com a finalidade de ajudar no diagnÃstico de falhas em sistemas computacionais com multiprocessadores Desde entÃo o estudo sobre esses cÃdigos e suas variantes tem sido desenvolvido Antoine Lobstein mantÃm uma bibliografia com mais de 200 artigos sobre o assunto A ideia do problema consiste em identificar qualquer vÃrtice do grafo utilizando apenas o seu conjunto de identificaÃÃo que sÃo os vÃrtices de sua vizinhanÃa fechada que estÃo no cÃdigo de identificaÃÃo Muitos estudos recentes se concentraram em grafos infinitos e com isso o objetivo à obter cÃdigos de identificaÃÃo nesses grafos infinitos com a menor densidade possÃvel Em 2005 Ben-Haim e Litsyn provaram que a densidade de um cÃdigo de identificaÃÃo Ãtimo da grade retangular infinita à 7/20. Nessa dissertaÃÃo fazemos um estudo bibliogrÃfico apresentando vÃrios resultados existentes e fornecemos uma prova alternativa para a densidade 7/20 de cÃdigos Ãtimos em grades retangulares infinitas usando o mÃtodo da descarga
The identifying code problem was introduced in 1998 by Karpovsky as a way to help fault diagnosis in multiprocessor computer systems Since then the study of this problem and its variants has been developed Antoine Lobstein maintains a bibliography with more than 200 articles on this subject The idea of the problem is to identify any vertex of the graph using just its identifying set which are the vertices of its closed neighborhood in the identifying code Many recent papers have investigated infinite graphs and then the main objective is to obtain identifying codes in these infinite graphs with the smallest possible density In 2005 Ben-Haim and Litsyn proved that the density of an optimum identifying code in the infinite rectangular grid is 7/20 In this dissertation we present a bibliographical study showing several existing results and we provide an alternative proof to the density 7/20 for optimum identifying codes in infinite rectangular grids using the discharging method

L'utilisation de schémas numériques d'ordre élevé est généralement restreinte à des applications de recherche mettant en jeu des phénomènes physiques complexes mais des géométries simples à l'aide de maillages Cartésiens ou faiblement déformés. Il existe une demande pour une nouvelle génération de codes industriels ayant une précision accrue. Dans ce travail, nous avons été amenés à répondre à la question générale sur la façon de concevoir l'architecture d'un code CFD pouvant prendre en compte une variété de configurations géométriquement complexes, restant assez simple et permettant facilement l'implantation de nouvelles idées (méthodes numériques, modèles) avec un effort de développement minimal, et utilisant des schémas numériques d'ordre élevé ainsi que des modèles physiques avancés. Cela a nécessité des choix innovants en termes de langages de programmation, structure de données et stockage, et sur l'architecture de code, choix qui vont au-delà du simple développement d'une famille spécifique de schémas numériques. Une solution (code DynHoLab) alliant les langages Python et Fortran est proposé avec les détails sur les concepts à la base de l'architecture du code. Les méthodes numériques implantées dans le code sont validées sur des cas-tests de complexité croissante, démontrant en passant la variété des physiques et géométries actuellement réalisables avec DynHoLab. Puis, basé sur ce code, ce travail présente un moyen de gérer des géométries complexes tout en augmentant le degré de précision des méthodes numériques. Afin d'appliquer les régimes d'ordre élevé RBC à des géométries complexes, la stratégie actuelle consiste en une mise en œuvre multi-domaine sur des maillages recouvrants
High-order numerical schemes are usually restricted to research applications, involving highly complex physical phenomena but simple geometries, and regular Cartesian or lowly deformed meshes. A demand exists for a new generation of industrial codes of increased accuracy. In this work, we were led to address the general question of how to design a CFD code architecture that: can take into account a variety of possibly geometrically complex configurations; remains simple and modular enough to facilitate the introduction and testing of new ideas (numerical methods, models) with a minimal development effort; use high-order numerical discretizations and advanced physical models. This required some innovative choices in terms of programming languages, data structure and storage, and code architecture, which go beyond the mere development of a specific family of numerical schemes. A solution mixing Python and Fortran languages is proposed with details on the concepts at the basis of the code architecture. The numerical methods are validated on test-cases of increasing complexity, demonstrating at the same time the variety of physics and geometry currently achievable with DynHoLab. Then, based on the computational framework designed, this work presents a way to handle complex geometries while increasing the order of accuracy of the numerical methods. In order to apply high-order RBC schemes to complex geometries, the present strategy consists in a multi-domain implementation on overlapping structured meshes