In the last years, the increase of the fuel price and the need to reduce the greenhouse gas emissions have triggered the research on lowering the fuel consumption within the transport sector. The research not only involves the development of more efficient engines but also the exploration of new transportation paradigms. One promising approach is to create vehicle platoons, i.e. convoys of vehicles driving close to each other. Vehicles driving close behind benefit from the reduction of the air drag and hence their overall fuel consumptions are reduced. This work focuses on studying platoons of heavy-duty vehicles (HDVs). More specifically, the work analyzes real position data of an HDV fleet from one manufacturer. The objective is to determine the potentials to reduce the fuel consumption of the fleet through platoon formations, using low sampled GPS traces obtained from the fleet management system. Map matching and path inference algorithms have been developed to reconstruct the path of the vehicles on a given road network. The reconstructed paths are used to analyze the vehicles’ positions and inter-vehicle distances. Results show that the vehicles are widely spread. The average distance to the closest vehicle is greater than 20km, which limits the platoon opportunities. Although with limited platoon opportunities, potential fuel savings up to 0.14% of the whole fleet’s consumption have been obtained. Results suggest that fuel savings can be largely improved if the density of vehicles in the road network is increased.

No description available.

During my studies at the Ecole des Mines d'Albi-Carmaux, I did an internship at the Royal Institute of Technology (Kungliga Tekniska Högskolan) in Sweden to finalize my master. The subject of this exercise is positioned as the junction of two different research areas. There is on one hand the development of new analysis method of Enterprise Architecture (EA) and on the other the analysis of software architecture modularity. The entire mission concerns a method of analyzing the modularity of EA developed by Harvard  Business  School.  The  analysis  method  called "Hidden  Structure"  aims  to evaluate the components of software and isolate vulnerable or key components. This internship's main task is to develop the Enterprise Application Modularity module. It is a module dedicated to the modularity analysis according to the hidden structure method and  its  integration  with  the  Enterprise  Architecture  Analysis  Tool  (EAAT)  software developed by KTH. This project also needs to develop additional functionalities to support the calculations. Among these features, you can find support for instantiation of new models and automated generation of reports containing the results.

As a capacity mechanism is currently being designed in France, a new capacity market will be created. The French transmission system operator RTE needed to conduct some studies on this market behaviour and the parameter influences. This report analyses in detail the French capacity mechanism and presents a model of the capacity market in order to study it. It then introduces a simulator called CLeMix that uses this model to run Monte Carlo and Agent based simulations. Several studies concerning the actors strategies and possible use of market power are then presented and their results analysed.

In recent years there has been an increase in wind power plants installed out at sea. The generated power of wind turbine generators (WTGs) are collected through numerous subsea cables into a single hub, the offshore platform. Subsequently, this platform is interconnected with the onshore main grid through a further stretch of cable. In the event of a fault, a sudden increase in current, so called short-circuit current, will occur somewhere in the system. The short-circuit current will, depending on the duration and location of the fault, potentially harm the power system. In order to accurately determine the dimensions and rating of the equipment installed in the offshore wind power plant (OWPP), the magnitude of this current needs to be studied. Furthermore, depending on the country in which the OWPP is installed, the transmission system operator (TSO) might pose different low-voltage-ride-through (LVRT) requirements on the system. One such requirement is that the installed turbines should provide voltage regulation through injection of reactive current. A type of generator able to achieve this is a so-called fully-rated converter windturbine generator (FRC WTG). Through a power electronic interface, the reactive and active current components of the generator can be freely controlled. With a high level of reactive current injected during a fault in the OWPP, the short-circuit contribution from these FRC WTGs needs to be evaluated. In this master’s thesis, a method has been developed in order to determine the steady-state short-circuit contribution from multiple FRC WTGs. This methodology is based on an iterative algorithm, and has been implemented in the simulation tool PowerFactory. To evaluate the performance of the method, two case studies were performed. In order to improve simulation times, an already existing WTG aggregation model has been implemented to reduce the number of turbines in the test system. From the results, it is concluded that the method obtains the expected FRC WTG short-circuit currents with sufficient accuracy. Furthermore, the deviation from the expected results are evaluated using a numerical tool. This project was initiated and conducted at ABB in Västerås, Sweden.

There are open issues within the uctuation theory owing to the approximations invoked in regimes outside fully ionized collisionless plasmas. This includes laboratory and space environments where e ects of Coulomb collisions or collisions with neutrals or dust particles cannot be ignored. Molecular Dynamics simulations have the potential to address such parameter regimes which are intractable by the analytical approach. The numerical method employed in this work for the calculation of the space-time correlation function of density uctuations is based on molecular dynamics in (r, v) space using an importance sampling Monte Carlo. The outcome of these MD simulation is then transformed into Fourier space to enable comparison with the analytical results of the uctuation theory. The comparison is carried out in the regime of thermal collisionless fully ionized plasmas, with no drifts and neutral component, in order to verify the numerical approach, choose appropriate simulation and FFT settings and to estimate error bars on the features of the electron spectral density of uctuations.

Several previous theses and reports have shown that voltage variations, and other types of supply changes, can influence the performance and movements of trains. As part of a modular software package for railway focused calculations, the need to take into account for the electrical behavior of the system was needed, to be used for both planning and operational uses. In this thesis, different static models are presented and used for train related power flow calculations. A previous model used for converter stations is also extended to handle different configurations of multiple converters. A special interest in the train type IORE, which is used for iron ore transports along Malmbanan, and the power systems influence to its performance, as available modules, for mechanical calculations, in the software uses the same train type. A part of this project was to examine changes in the power systems performance if the control of the train converters were changed, both during motoring and regenerative braking. A proposed node model, for the static parts of a railway power system, has been used to simplify the building of the power system model and implementation of the simulation environment. From the results it can be concluded that under normal conditions, for the used train schedule, the voltage variation should not restrict the trains traction performance. It can also be seen from the results that a more optimized power factor control with a higher regenerative brake power or generation of reactive power could be used to limit the need for investments in infrastructure or to increase the traffic for a given system layout. / I ett flertal tidigare undersökningar och rapporter har konstaterats att spänningsvariationer, och andra förändringar, hos strömförsörjningen till tåg kan påverka dess prestanda och dess färd längs rälsen. Som en del av ett modulärt programpaket för tågrelaterade beräkningar uppstod därför ett behov av elkraftsberäkningar, både för planering och operativ drift. I denna rapport sammanställs och används ett antal olika statiska modeller för tågrelaterade effektflödesberäkningar. Modellen för omformarstationer har även utökats för att hantera konfigurationer då olika typer av omformare används. Ett särskilt intresse för tågtypen IORE, som används för malmtransporter längs Malmbanan, och dess påverkan av en förändrad strömförsörjning, har funnits då olika typer av mekaniska beräkningar för denna tågtyp utförs i andra befintliga moduler. En del av projektet bestod i att undersöka förändringar i elförsörjningen, på grund av en ändrad styrning av tågens omformare, både vid återmatning och motordrift. En föreslagen nodmodell för den statiska delen av elnätet har använts för att förenkla elsystemsmodellen och uppbyggnaden av simuleringsmiljön. Av resultaten från simuleringarna kan man anta att under normala förhållanden, och med det använda körschemat, bör ej spänningen vara en begränsande faktor för tågens drift. Övriga simuleringar visar också att en mer optimerad effektfaktor för högre återmatad bromseffekt eller för generering av reaktiv effekt kan användas för att slippa investeringar i infrastrukturen, eller för att utöka trafikmängden för ett givet system.

Load shedding events are a major concern today for the Senegalese power grid, which production, transport, distribution and selling are operated by the national power company SENELEC. Even if some improvements have been made these last years through important power plant renovation campaigns, unserved energy still represented 1.5% of the total power demand in 2013. These events are mainly due to two factors: grid failure or work on the one hand (65% of unserved energy in 2013) and production lack or failure on the other hand (35% of unserved energy in 2013). If grid failure problems are being tackled by some rehabilitations and extension of the network, production lack problems will only be solved on the long term by setting up new power plants to face the increasing power demand. In order to face these power shortages, many customers have installed their own generation sources, mostly diesel generators used in case of emergency, but also more recently photovoltaic panels to both ensure power supply reliability thanks to storing batteries and reduce their electricity bills. These installations represent an important power production still unexploited today by SENELEC. The goal of this Master Thesis was then to see the potential use that could be made of these generation sources to reduce unserved energy in the short term. Diesel generators could thus be used for voluntary load shedding if properly implemented and photovoltaic installations could be connected to the grid to inject their production surplus. These two solutions were studied both from a technical and economical point of view, and their potential impact on unserved energy reduction was quantified. The results show that voluntary load shedding could actually reduce the amount of unserved energy due to production lack or failure by 40% to 80%, and that it is economically viable compared with other solutions such as production capacity renting. They also show that it is possible to connect domestic-scale photovoltaic installations to the low voltage grid without any negative impact on its operation in most of the situations met today. Finally, some recommendations were made, including proposals for voluntary load shedding implementation and the setting up of a dedicated team at Senelec for photovoltaic integration studies.

Nowadays, with the increasing need for security and economic operation of power systems, the optimal power flow (OPF) has been an essential and predominant tool for economic and operation planning of power systems. A developed conic formulation for OPF has been proposed [1]. This model is bases on the line based flow equations and can be transformed into the form of second order cone programming (SOCP). The SOCP formulation of OPF problem can be solved using interior point methods (IPMs) [2]. In this thesis, a study on the performance of this developed conic formulation for OPF is carried out. Firstly, the accuracy of SOCP formulation is studied. A more accurate model is developed. The model is obtained by modifying the phase angle constrains of SOCP formulation. The modified model can be solved using sequential conic programming method. A comparison of results from these two models is made on different test systems. Secondly, the SOCP formulation is applied to both small and large test systems. The results of SOCP formulation is compared with the results from PSS/EOPF. The performance of SOCP formulation has shown the accurate and effectiveness for solving OPF problems.

Renewable energy sources help reaching the environmental, social and economic goals of producing electrical energy in a clean and sustainable matter. Among the various renewable resources, wind power is assumed to have the most favorable technical and economic prospects and offers signicant potential for reducing greenhouse gas (GHG) emissions. As wind power installations are more and more common in power systems, additional research is needed in order to guarantee the quality and the stability of the power system operation. Maintaining the frequency as close as possible to its rated level is one of the most important tasks for grid operators in order to maintain a stable electricity grid. However, the signicant penetration of wind generation in power grids has raised new challenges in the operational and planning decisions of power systems. Wind turbine units almost always include power converters decoupling the frequency dynamics of the wind power generators from those of the grid. This decoupling causes a reduction in the total system inertia, affecting the system's ability to overcome frequency disturbances. To study the impact of wind power on the system inertia, first the Nordic 32-A System, representing a scaled version of the Swedish grid, is implemented in PSS/E. A system identication of model parameters with actual data follows. This ad-hoc identification method determines the dynamic parameters of the governors and prime movers in the model. The two metrics of primary frequency control; the instantaneous minimum frequency and the rate of change of frequency (ROCOF) are simulated using the identified power system, and via an extrapolation, the maximum wind power penetration in Sweden is found, considering that the system has to comply with the instantaneous minimum frequency requirements and also that the tripping of the generators' ROCOF relays is prevented. The second part of the work focuses on an economic study of the cost to guarantee an adequate frequency response, particulary the Primary Reserve (PR). The Primary Reserves is the capacity of the generators that is reserved for the governors to use for Primary Frequency Control (PFC). Primary Reserves also include the ramping capability requirement of power plants for regulating power imbalances caused by contingencies. Recent studies have shown that having more renewable resources, such as wind with no PFC capability as well as an electricity market design with no incentive for PFC, are important drivers for a decline in the frequency response in the system. One solution is the careful design of a PFC ancillary service market by introducing suitable constraints to ensure the adequacy of Primary Frequency Control. However, applying these constraints will increase the generation cost especially when more and more windpower is integrated. This work proposes the use of an adequacy constraint to evaluate the economic impact of wind integration with respect to its influence on guaranteeing an adequate PFC. To analyze the cost increment for maintaining an adequate frequency response in the presence of wind power, an optimal power ow (OPF) problem is designed with an objective function of the generation cost minimization and considering a PFC adequacy constraint. The results show that the inclusion of the new constraints in the optimal dispatch OPF leads to a higher dispatch cost.