POWER DISTRIBUTION

Author: GOMEZ CUENCA FELIX.
Year: 2004.
University: OVIEDO [www.uniovi.es].
Place of defense: ETSIMO ESCUELA TECNICA SUPERIOR DE INGENIEROS DE MINAS.
Place of preparation: ETSIMO.

Summary: Virtually all policies and strategies on energy agree on the relevance of four key components:. Improving energy intensity. Diversification. Security of supply. Improving environmental performance reasons vary greatly, the transportation of oil and fuel derivatives is a key activity in the value chain for these products, both in terms of strategic and economic. Such transport can be done by various means, including, vessels greater capacity and pipelines listed as lower cost and better energy intensity. Despite its high efficiency, energy consumption represents a significant percentage of the total cost in transport pipelines. If you join this circumstance those arising from the components already sefialados as a key strategy and energy policy, we found that the decrease of energy consumption in transport by pipeline represents an initiative of great interest both for companies directly involved and for the environment acting. The reduction of energy consumption in transportation pipelines can be approached from different perspectives. In this paper addresses from the exploitation of the so-called "Toms effect" which involves the reduction of friction that occurs when a fluid that is carried by a pipe he added pequefias amounts of polymeric compounds that, for this reason, they usually called additives reducing friction (Drag Reducing Additives, DRAs). By implementing a series of extensive tests in actual pipeline has quantified the reduction of friction that. Get two DRAs last generation. There were also quantified the energy savings derived from the use of such additives and improvements in other variables, such as the needs of installed power. Collected data and the data of the pipeline network in Europe has made an estimate of potential savings, at the European level could be obtained as a result of the widespread use of these products. From energy saving potential has been estimated to reduce CO2 emissions associated with it. Fuels behave as Newtonian fluids, and therefore their behavior is consistent with the equations already developed for these fluids. These eclaciones are currently being incorporated into applications and operating control of pipelines. By contrast, fuel aditivados with DRAs not behave as Newtonian fluids and the same can not apply the above equations. From the data obtained from trials in the pipeline has developed a model that describes and predicts the behavior of fuels aditivados with DRAs, this model can be incorporated into applications pipeline operation and control when these additives are used. We have conducted numerous tests on characterization and analysis of fuel to assess the extent to which the presence of DRAs affects their quality and performance. We have identified those properties of the fuel are affected by the presence of DRAs and has revealed the relationship that infl 8 uencia c 764 on the molecular weight of DRAs. The molecular weight of DRAs is a variable criticizes, therefore, has developed a method for detecting the DRAs into liquid fuels, using gel permeation chromatography on. There have been various laboratory tests show that the decrease in molecular weight of additives in transport by pipeline, the decline has been quantified in a real trial in transport by pipeline. It has also studied the effectiveness of ultrasound as an alternative method of decreasing molecular weight of DRAs and has established a relationship between the effectiveness and energy radiated. The behavior of engines and vehicles should not be affected by the presence of DRAs on fuel. It has conducted a series of extensive tests on motor bank and an essay on motor vehicle revealed a lack of influence of DRAs on the aspects evaluated, except an increase in deposits generated in some parts of the engine, compared magnitude generated by other additives commonly used or widely used in fuels.

Author: DIOLETTAS STAMATIS.
Year: 2005.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: 28.8 (ETSEIB).
Place of preparation: ETSEIB, EDIFICI H PLANTA 10 Campus SUD.

Summary: Energy problem is a prime issue in the agenda of European and international society. European Union energy policy aspires to secure future energy supplies and to shrink the environmental problems stemming from energy production and use. Renewable energy technology is one of the options for meeting European policy targets. Despite, the support of European Union and its member states renewable energy technology's diffusion was slow. Renewable energy technology is an innovation for the energy system. Moreover, technological change is a social process. Innovations are produced and diffused because there are social actors who have interests and expect benefits from new technologies. Instead of studying renewable technology in isolation, they are examined the technological systems in which it can be introduced; the existing electric power system and the distributed energy resources (DER). DER is an energy system that includes small-scale power generation, storage and demand-side-management technologies. The conceptual tool used for the facilitation of our analysis, was technological regime. With the term regime is meant how the technological system coordinates and organises its actions; what physical resources it uses and what is the institutional framework of the interaction rules with other institutions and social entities. Finally, all the above define its political power and consequently its political attitude within society. It is the novelty of this thesis the use of the aforementioned methodology. The "holistic" approach to the problem of technological change brings into the light parts that before remained in the shade. The technological regime imposed by the existing energy system sustains centralised, large-scale technology, organisations and capital invested. Large centralised power plants connected to the transmission network is the basic feature of existing system. The vastness of the system requires large quantities of physical resources. The sector is dominated by large organisations whose employers are counted in tenths of thousands while the decision-making is a privilege of few experts and managers. Communities receive the social and environmental impacts but they have little chance to intervene. DER, although it is hypothetical, will democratise energy system. Its regime will create the conditions for a decentralised, small-scale energy system in which innovations such as renewable technology will be welcomed. Small-scale technologies connected to the distribution system or in an "island" form would provide electricity to communities, commercial and industrial buildings or residential houses. Distributed generation reduces the vulnerability of the electric system due to human errors or to other physical phenomena. It does not need the concentration of mass quantities of physical resources. It is a flexible system adaptable to social and environmental conditions. Individuals and small-medium enterprises would play a major role in distributed energy resources development. This will result in a decentralised decision-making by which communities could make their energy choices compatible with their cultural and political values. Communities in their effort to satisfy their energy needs and maintain their cultural and political objectives have come in a confrontation with the existing energy system. This confrontation may lead communities towards a different range of problem approaches, from trivial to revolutionary ones. Distributed energy resources from a pioneering, niche energy system could be a generalised solution for many communities. Four social characteristics will give it further competitiveness: (1) open to social intervention in all the project development phases, (2) sensible to local communities' concerns and (3) redistribution of economics benefits of the energy sector to a greater part of society 8 (4) redu 2dd ction of environmental impacts with the integration of renewable energy technologies

Author: ENCINAS REDONDO NURIA.
Year: 2006.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: Dep. Ingenieria Electrica.
Place of preparation: Universidad Politécnica de Valencia.

Author: BAQUI SADIK IBRAHEM.
Year: 2006.
University: PAÍS VASCO [www.ehu.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIERÍA DE BILBAO.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIERÍA DE BILBAO.

Summary: This thesis develops a new methodology for detecting faults in high impedance networks in electricity distribution, using wavelet transform and neural networks. So, from the intensity signals collected in the substation, the method is capable of distinguishing between a lack of high impedance, a lack of low impedance or a state of normal operation of the system in any of its circuits. To complete the discovery process, is a first preprocessing of data in intensity through the application of wavelet transform. This preprocessing enables une extraction features of the signal flow in the frequency domain, both for high to low frequencies. These features, specific to each state of operation, were later introduced as input data into a neural network. Thus, for each circuit is in a state of normal operation or being subjected to a lack of low or high impedance.

Author: AURTENECHEA LARRINAGA SERGIO.
Year: 2006.
University: MONDRAGÓN UNIBERTSITATEA [www.mondragon.edu].
Place of defense: MONDRAGON GOI ESKOLA POLITEKNIKOA.
Place of preparation: MONDRAGON GOI ESKOLA POLITEKNIKOA-MONDRAGON UNIBERTSITATEA.

Summary: The objective of this thesis is the development of new control algorithms for converters directly connected to networks MT task regulatory power. It assesses two topologies converters DC / AC widely used in industry; converter bi-nivel and tri-nivel NPC. In this context, integrates knowledge of the techniques of classical control VOC (Voltage Oriented Control) along with the strategies of direct control DPC (Direct Power Control), defining a new perspective control oriented converters with high power restrictions frecuenciales. Thus, establishing the theoretical foundations of a new type of predictive algorithm, the Predictive Direct Power Control (P-DPC). The features of this algorithm allow the development of different versions, anadiéndole greater versatility with regard to control techniques usual. Various simulation results and the experimental show levels of quality power in the permanent regime comparable to those obtained with conventional control techniques but substantially higher in transitoriios. Thus, we concluded that the P-DPC can become an interesting alternative to the usual techniques for VOC converters connected to the electricity grid.