Since November 2010, the French, Belgian, German and Dutch electricity markets are sharing a common mechanism for Day Ahead price formation called “Market Coupling”. This implicit auctioning system for cross border flows management is part of a regional market integration policy which constitutes an intermediary step toward fully integrated European markets. Within a few years, power markets had evolved a lot, and faced many changes (completion of the deregulation process, renewable integration, …). They were also indirectly affected by the consequences of the Japanese nuclear catastrophe in 2011. In this context, it is interesting to take a stock on the convergence process between these four countries, less than a year after the coupling was launched. Studying the convergence and its evolution for both spot and futures prices can give precious information in order to implement hedging strategies. In this thesis, we explore the dynamics of the convergence process through two main analyses: a Kalman filter and a more original approach based on Mean Reversion Jump Diffusion parameters estimation. We also describe and explore the convergence process under the light of market organisation, production portfolios and consumption profiles to highlight similarities but also divergences. Despite a European framework suitable for convergence, we observe major differences in energy mixes, consumption profiles and renewable integration rates. However, prices are showing significant convergence patterns through the years. Indeed, we observed that the relation between prices was getting steadier and that the price spread was narrowing. Besides, we also noticed that such a convergence process was not constant but rather stepwise and could be affected by peculiar events. France, Belgium, Netherlands and Germany’s electricity markets are already well integrated and seem to converge further but sudden changes can appear. This is why a hedging strategy between these countries is feasible but implies some risks.

As the electric consumption increases and the constraints multiply, the grid becomes weaker and may not be able to face critical voltage stability problems. Indeed, in the past decades some blackouts occurred in Europe and America, due to voltage instabilities. At a 5-year horizon, new lines or new power plants cannot be built in time, it is therefore necessary to invest in capacitors to prevent voltage collapses. The core of this project is the best localization of these investments, to make the grid strong enough to bear a major fault in an already difficult situation. The first part of the master’s project is the development of a new method which permits to decide where to install new capacitors based on a dynamic approach. The second part consist on simulations performed on a specific part of the French grid. Each simulation was the subject of a variation of one of the different parameters or elements of the situation. These simulations have a double goal: to validate the method by examining the consistency of the different results, and to have a first idea of the impacting parameters, or their influence on the number of capacitor which should be installed, and their localizations.

This master thesis is a study of the Swedish hydropower capacity to balance wind power. The Swedish government has decided that it should be possible to produce 30 TWh from wind power in the year 2020. The Swedish municipalities have to have plans for wind power plants with total yearly generation of 30 TWh. Wind power is an variable energy source that needs to be balanced by other energy sources. In Sweden the Swedish hydropower can be used for balancing a large scale introduction of wind power. The hydropower balancing capacity is examined in a model with 256 hydropower plants with a total installed capacity of 15 640 MW. The Swedish hydropower production is simulated for a total of twelve weeks from the year 2009. The model has a resolution of one hour and considers the existing water permits and is an extension of the one used in the report Elforsk 09:88 Balancing of wind power with hydropower in northern Sweden. Transmission capacity constraints between Sweden and the countries Sweden is connected to and in between the four price areas in Sweden are included. Consumption of electricity, other electricity generation and wind power are in the form of time series. In practice, the hydro power’s ability to follow given variable net load is simulated. Different levels of installed wind power, wind and available export capacity are examined. An introduction of 4000 MW, 8000 MW and 12 000 MW wind power are simulated. The key finding is that the spillage of water does not increase with increased amount of wind power. Spillage occurs when too much electricity is generated. The spillage can be avoided with modified seasonal planning. There is no seasonal planning in the model since the model only simulates over one week. In the model export of electricity is assumed to be possible, a large wind power generation implicates a low electricity price. A wind power plant owner always wants to sell his or her generation no matter what electricity price is. Export from Sweden is assumed possible with an amount corresponding to available transmission capacity to other countries. A large scale introduction of wind power will increase Sweden’s export of electricity. Norway also has plans to build more wind power and Finland is building new nuclear power plants. There might be problems to find use for all electricity generated. On the continent the prices and demand for electricity are higher. The Polish and German electric grids are weak and can’t receive large amounts of electricity. If Germany and Poland can’t receive electricity due to internal bottlenecks, the System operators are decreasing the capacity on the connections to Sweden. In North Germany there is a lot of wind power that is a contributing factor, when the power generation is high., In these situations Germany can receive less electricity from Sweden. Electric district heating and maybe electric vehicles can in the future consume an oversupply of electricity. A large scale introduction of electric vehicles can increase the Swedish electricity consumption by 9 TWh. Alternatives to balancing with conventional hydropower are also briefly discussed. Un‐natural and heavily variable flows can affect animals and plants in a negative way. Among alternatives are pumped ‐storage hydro, gas turbines, heat power plants on and smart grids in this case of flexible load.

Storage system is one of the critical components of the microgrid. Storage system has broad applicability in short-term and long-term operations of microgrid. Storage systems are fast response devices which add flexibility to the control of the microgrid, and furthermore provide economical benefits by storing energy at times of excess power and generating energy at times of low generation. Moreover, storage systems can mitigate the frequent and rapid power changes of renewable resources and therefore solve the volatility and intermittency problems associated with renewable resources. The storage systems has existed for many decades, however, the impact of storage systems in future grids, incorporating microgrids, is receiving more attention than ever from system operators. In addition, the storage systems continue to evolve as new technologies are introduced. Considering these issues, modeling of the storage systems operation would an essential task to help operators in enhancing the microgrid operation from both economical and security points of view. The microgrid security means that a feasible power flow solution should be obtained in base case and contingency operation of microgrid. The base case is the normal operation of the microgrid when there is no outage in components. In contingency cases, however, some of the generating units and/or transmission lines would be out of service. The robust operation of the microgrid, as well power system in general, requires consideration of contingencies. If possible system contingencies are not determined and taken into account, dramatic and costly blackouts are likely to happen, which would provide inconvenience and unexpected costs for electricity customers. Therefore, contingencies are considered in microgrid operation so that the microgrid will operate at all times and unwanted events, such as instability, voltage collapse, and cascaded outages would not occur. In this report, the economic and emergency operations of the storage system in the microgrid are investigated. In base case operation of the microgrid, the storage system provides economic benefits by storing energy at times of low electricity prices and using the stored energy at times of high electricity prices. Accordingly, it facilitates peak shaving and load shaping and results in reduction in electricity costs. In emergency cases, when there is a microgrid component outage and we have contingencies, the storage system would be used as a generation resource to compensate the lost generation due to generating unit outages, and furthermore satisfy system security. Preventive (precontingency) and corrective (post-contingency) actions of storage system are taken into consideration in the security-constrained unit commitment (SCUC) problem. The cost of system operation is minimized and at the same time the system security is satisfied. Appropriate storage system corrective and preventive control actions for managing contingencies represent a trade-off between economics and security in a microgrid. Both actions are introduced and compared, since the preventive dispatch is very conservative and could be expensive for considering all potentially dangerous contingencies, and in contrast, the corrective action only applies to allowable post-contingency control adjustments. A complete formulation of the SCUC problem in the microgrid incorporating a practical storage system model is presented. Mixed integer programming(MIP) will be used to formulate the problem.

In this thesis, we propose a H.264-compatible temporal subband coding scheme for static background scenes of soccer video. We utilize the orthonormal wavelet transform to decompose a group of successive frames into temporal subbands. By exploiting the energy conservation property of the orthonormal wavelet transform, we construct a rate distortion model for optimal bitrate allocation among different subbands. To take advantage of high efficiency video codec H.264/AVC, we encode each subband with H.264 intra-coding by assigning optimal bitrates. The experimental results shows that our proposed coding scheme outperforms conventional video codec H.264/AVC and VP8 for both subjective and objective evaluation.

The recently introduced compressive sensing (CS) theory allows – under certain assumptions – to recover a signal sampled below the Nyquist sampling limit. Compressive sensing can be applied for two purposes. First, to decrease the number of samples needed to capture the information, thus allowing faster acquisitions. Second, to improve the reconstruction of signals/images in fields where constraints on the physical acquisition setup yield very sparse data sets. This thesis focuses on medical ultrasonography, with the two following applications: First, 3D imaging using a matrix array of sensors. In this field, a major difficulty concerns the number of elements that are used to acquire the image. For technical reasons, only a fraction of the sensors can be used, which leads to a typical application for the CS theory. Second, duplex acquisitions for B-mode/Doppler imaging. Duplex acquisition implies the alternation between two modes of emission, thus giving sparse velocity measurements. Compressive sensing offers a way to recover the Doppler signal by circumventing the Nyquist-Shannon sampling theorem.

Due to the Internet expansion over the last decades, the pressure for the telecommunications companies to deliver a high performance broadband communication, especially wireless is imminent. Future wireless networks will need to support high data rates in order to meet the requirements of multimedia services. Furthermore, the user density will be much higher for every year and it will be an increase of amount of data communication between mobile devices. Consequently, a new generation network has been introduced, i.e. LTE also called 4G, promising better performance and speed. Nevertheless, it is not only the network that plays an important role in achieving speed and performance, but also the communication system including number of antennas used, antenna deployment, power, number of base station, and so on. Most research papers agree on one point and this is the fact that the performance and reliability may be improved when using multiple inputs and/or multiple outputs, i.e. MIMO. This Master Thesis concerns the performance acquired by studying on one hand the capacity achieved by using multiple antennas in the receiver (1 x 4 MIMO) and on the other hand studying different methods used by the base stations for scheduling the transmission to users according to their channel quality. Furthermore, the evaluation has been done numerically using measured radio channels, obtained by Ericsson. One of the methods used in this paper is opportunistic scheduling, which involves the tracking of each of the fading users’ channel fluctuation and scheduling transmission to these users when their instantaneous channel quality is close to their maximum. In order to improve the communication of those users with low channel quality, a well-known algorithm was added to the Opportunistic scheduling. This method considers previous capacity rates and it is called Proportional Fair scheduling. Another effect of using the Opportunistic scheduling is the suppression of the inter-cell interference (ICI) generated by close-by base stations, called Opportunistic nulling. In this paper, Opportunistic nulling is analysed in order to find out whether a practical suppression is achieved by this scheduling and whether factors such as delayed channel information may affect the scheduling and prevent a reliable communication with minimum interference.

In this paper two methods for thermally modelling the Synchronous Reluctance Machine (SynRM) have been developed and compared to measured data. The first is an analytical method for estimating the end winding temperature based on Brostr¨oms formula. Curve fitting to the measured data was done by Gauss-Newton estimation. The second method uses a lumped thermal network for steady state temperature estimation based on machine geometry. Thermal modelling of the machine parts are portrayed. The frame to ambient thermal resistance is derived from measured data. Friction and windage losses are calculated through measurement, the core losses are separated based on finite element calculations. The results for both methods show good agreement. A comparison between the different methods is made.

Traction motors are thermally pressed to obtain a high torque per unit volume at the same time as a relatively high frequency is used. Because of the high frequency the phenomenon skin effect and proximity effects appear, this is explored in the thesis. To find a link between the parasitic and thermal effects on the insulation is important. In this thesis, a finite element model of the Flux 2D suitable for skin effect analysis is developed; also a thermal network has been developed to find thermal hotspots in the stator slot. In this thesis, sinusoidal supplies for two operating points are studied and triangular sinusoidal PWM supply is as well studied for the nominal operating point.

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