By using IT-solutions, the flexibility on the demand side in the electrical systems could be increased. This is called demand response and is part of the larger concept called smart grids. Previous work in this area has concerned the utilization of demand response by grid owners. In this thesis the focus will instead be shifted towards the electrical companies that have balance responsibility, and how they could use demand response in order to make profits. By investigating electrical appliances in hourly measured households, the business value from decreasing electrical companies’ power imbalances has been quantified. By an iterative simulation scheme an optimal value was found to be 977 SEK/year and appliance. It could however be shown that the value became larger for energy inefficient households, and that such consumers’ participation in a demand response market would be prioritized ahead of other measures like isolating walls is rather unlikely. Thermal appliance whose load depend on the outdoor temperature are less valuable for demand response during the summer months, and the annual value would increase if less seasonally dependent appliances were used. Additionally, by increasing the market price amplitudes and the imbalance price volatility, it could be shown that the potential for such demand response markets is larger in e.g. the Netherlands and Germany.

No / In this study, a new methodology to optimally allocate wind turbines (WTs) in distribution networks is proposed. A market-based optimal power flow is used to determine the optimal numbers and capacities of WTs in a way that maximises the social welfare. The method is conceived for distribution network operators to strategically allocate WTs in distribution networks. The proposed method by yielding location-specific WTs capacity settlement both in terms of cost reduction and consumers' benefits is consistent with distribution network topology and constraints. The method is solved by using step-controlled primal dual interior point method considering network constraints. The effectiveness of the proposed method is demonstrated with two radial distribution systems including an 84-bus 11.4 kV and a 69-bus 11 kV network.

This research focuses on improving the efficiency of power market operations by providing system operators additional tools for managing the costs of supplying and delivering electricity. A transmission topology control (TC) framework for production cost reduction based on a shift factor (SF) representation of branch and breaker flows is proposed. The framework models topology changes endogenously while maintaining linearity in the overall Mixed Integer Linear Programming (MILP) formulation. This work develops the DC lossless, and loss-adjusted TC formulations that can be used in a Day Ahead or intra-day market framework as well as an AC-based model that can be used in operational settings. Practical implementation choices for the Shift Factor formulation are discussed as well as the locational marginal prices (LMPs) under the TC MIP setting and their relation to LMPs without TC. Compared to the standard B-theta alternative used so far in TC research, the shift factor framework has significant computational complexity advantages, particularly when a tractably small switchable set is optimized under a representative set of contingency constraints. These claims are supported and elaborated by numerical results.

<p>In this thesis we focus resource allocation problems and electronic markets in particular. The main application area of ours is electricity markets. We present a number of algorithms and include practical experience.</p><p>There is an ongoing restructuring of power markets in Europe and elsewhere, this implies that an industry that previously has been viewed as a natural monopoly becomes exposed to competition. In the thesis we move a step further suggesting that end users should take active part in the trade on power markets such as <i>(i)</i> day-ahead markets and <i>(ii) </i>markets handling close to real-time balancing of power grids. Our ideas and results can be utilised <i>(a) </i>to increase the efficiency of these markets and <i>(b) </i>to handle strained situations when power systems operate at their limits. For this we utilise information and communication technology available today and develop electronic market mechanisms designed for large numbers of participants typically distributed over a power grid.</p><p>The papers of the thesis cover resource allocation with separable objective functions, a market mechanism that accepts actors with discontinuous demand, and mechanisms that allow actors to express combinatorial dependencies between traded commodities on multi-commodity markets. Further we present results from field tests and simulations.</p>

In this thesis we focus resource allocation problems and electronic markets in particular. The main application area of ours is electricity markets. We present a number of algorithms and include practical experience. There is an ongoing restructuring of power markets in Europe and elsewhere, this implies that an industry that previously has been viewed as a natural monopoly becomes exposed to competition. In the thesis we move a step further suggesting that end users should take active part in the trade on power markets such as (i) day-ahead markets and (ii) markets handling close to real-time balancing of power grids. Our ideas and results can be utilised (a) to increase the efficiency of these markets and (b) to handle strained situations when power systems operate at their limits. For this we utilise information and communication technology available today and develop electronic market mechanisms designed for large numbers of participants typically distributed over a power grid. The papers of the thesis cover resource allocation with separable objective functions, a market mechanism that accepts actors with discontinuous demand, and mechanisms that allow actors to express combinatorial dependencies between traded commodities on multi-commodity markets. Further we present results from field tests and simulations.

The main target of this thesis is to summarize and explain the specifics of power markets and test application of models, which might be used especially in risk management area. Thesis starts with definition of market subjects, typology of traded contracts and description of market development with focus on Czech Republic. Thesis continues with development of theoretical concepts of short term/spot electricity markets and potential link between spot and forward electricity markets. After deriving of those microeconomic fundamental models we continue with stochastic models (Jump Diffusion Mean Reverting process and Extreme Value Theory) in order to depict patterns of spot and forward power contracts price volatility. Last chapter deals with credit risk specifics of power trading and develops model (using concept known as Credit Value Adjustment) to compare economic efficiency of OTC and exchange power trading. Developed and described models are tested on selected power markets, again with focus on Czech power market data set.

As open access market principles are applied to power systems, significant changes are happening in their planning, operation and control. In the emerging marketplace, systems are operating under higher loading conditions as markets focus greater attention to operating costs than stability and security margins. Since operating stability is a basic requirement for any power system, there is need for newer tools to ensure stability and security margins being strictly enforced in the competitive marketplace. This dissertation investigates issues associated with incorporating voltage security into the unbundled operating environment of electricity markets. It includes addressing voltage security in the monitoring, operational and planning horizons of restructured power system. This dissertation presents a new decomposition procedure to estimate voltage security usage by transactions. The procedure follows physical law and uses an index that can be monitored knowing the state of the system. The expression derived is based on composite market coordination models that have both PoolCo and OpCo transactions, in a shared stressed transmission grid. Our procedure is able to equitably distinguish the impacts of individual transactions on voltage stability, at load buses, in a simple and fast manner. This dissertation formulates a new voltage stability constrained optimal power flow (VSCOPF) using a simple voltage security index. In modern planning, composite power system reliability analysis that encompasses both adequacy and security issues is being developed. We have illustrated the applicability of our VSCOPF into composite reliability analysis. This dissertation also delves into the various applications of voltage security index. Increasingly, FACT devices are being used in restructured markets to mitigate a variety of operational problems. Their control effects on voltage security would be demonstrated using our VSCOPF procedure. Further, this dissertation investigates the application of steady state voltage stability index to detect potential dynamic voltage collapse. Finally, this dissertation examines developments in representation, standardization, communication and exchange of power system data. Power system data is the key input to all analytical engines for system operation, monitoring and control. Data exchange and dissemination could impact voltage security evaluation and therefore needs to be critically examined.

Made available in DSpace on 2016-08-17T14:53:12Z (GMT). No. of bitstreams: 1 Romel Jimenez.pdf: 804071 bytes, checksum: 8f161d1f48519af0d6ee9068f4876a93 (MD5) Previous issue date: 2007-02-26 / In this work a methodology based on linear programming for long-term hydrothermal scheduling of electric power systems is proposed. The objective of the hydrothermal scheduling is to find an optimal operation for a specific time interval and with high reliability and minimum cost. That is equivalent to determine an optimal generation scheduling for the power plants and for each time interval considered, in order to the power system satisfies the forecasted demand. Linear models of the power system components are adopted, and with the option to solve systems with multiple reservoirs and buses. It was implemented a computer program using MATLAB platform for application to small test power systems and configurations of real-size systems such as the interconnected Peruvian System and the Brazilian South-Souheast System. For the solution of the linear optimization problem was used the interior points method. From the analysis of the test systems results is concluded that the linear model may capture adequately the relevant characteristics of the real power system and it may be eficient and precise such as the detailed model. / Neste trabalho é proposta uma metodologia baseada em programação linear para a solução da coordenação hidrotérmica de longo prazo de sistemas de energia elétrica. O objetivo da coordenação hidrotérmica é encontrar uma política de operação ótima em um determinado período de tempo, com alta confiabilidade e custo mínimo. Isto equivale a determinar um cronograma ótimo de geração para cada usina, a cada intervalo de tempo, de modo que o sistema atenda a demanda prevista. Adotam-se modelos lineares dos componentes do sistema de potência, com a opção de resolver sistemas com múltiplos reservatórios e múltiplas barras. Foi implementado um programa computacional em MATLAB para a solução de sistemas teste de pequeno porte e configurações de sistemas de potência reais tal como o Sistema Interligado Peruano e o Sistema Brasileiro da Bacia Sul-Sudeste. Para a solução do problema de otimização linear foi utilizado o método de pontos interiores. Da análise dos resultados com os sistemas teste conclui-se que o modelo linear pode capturar adequadamente as características relevantes do sistema real e pode ser tão eficiente e preciso quanto o modelo detalhado.

This thesis deals with application of optimisation methods based on linear and mixed-integer linear programming to various problems in the power sector related to electricity production. The thesis goal is to test the applicability of such methods to formulating and solving various instances from the class of real-world electricity production problems, and to find the advantages and disadvantages associated with using these methods. Introductory chapters describe the main characteristics of power markets, including the historical and regulatory context. Fundamental properties of power markets on both demand and supply side are also described, both from a real-world and a modelling point of view. Benefits of optimisation and modelling are discussed, in particular the solution feasibility and optimality as well as insights gained from sensitivity analysis which is often difficult to replicate with the original system. In the core of the thesis, optimisation techniques are applied to three case studies, each of which deals with a specific problem arising during electricity production. In the first problem, the profit of gas-fired power plant in Slovakia from selling power on the day-ahead market is maximised. The model is set up using both technical and commercial constraints. The second problem deals with the problem of representing a two-dimensional production function which primarily arises for a hydro generator with large variations in the level of its reservoir. Several representations of the original function using piecewise linear subsets are presented, compared, and characterised by their computational intensity both theoretically and practically. In the third problem, the prices on the German day-ahead market in 2011 are modelled. Contrary to the previous two models, the model does not capture an optimisation problem faced by a single producer, but incorporates a large subset of the whole market instead. Consequently the model is formed out of generic constraints relevant to all power plants whose parameters are estimated. By combining information about the aggregate availability of power plants with the estimated efficiencies a full supply curve for each day is created. Different scenarios are analysed to test the impact of uncertain inputs such as unknown or estimated constraints. The choice of the investigated problems stems from the attempt to cover electricity production problems from the point of view of multiple criteria. The three investigated electricity production problems span a broad range from the decisions of a single power plant to the modelling a power market as a whole. Formulations of the production function with different level of detail are presented ranging from a simple linear relationship to several bivariate function formulations. While each problem answers a specific question, they all illustrate the ease with which various electricity production problems can solved using optimisation methods based on linear and mixed-integer linear programming. This is mainly due to the ability of these methods to approximate even non-linear functions and constraints over non-convex domains and find global solutions in reasonable time. Moreover, models formulated with these methods allow sensitivity and scenario analyses to be carried out easily as is illustrated in each of the case studies.

El sector eléctrico de muchos países pasó por un proceso de reestructuración que tuvo su inicio en las décadas de los 80 y 90, cuyo objetivo era reorganizar el funcionamiento del sector eléctrico, mejorando su eficiencia y proporcionando así beneficios a largo plazo a los consumidores, como la reducción del precio de la electricidad. En España, este proceso se inicia en la práctica con la aprobación de la Ley 54 del Sector Eléctrico en 1997, que establecía las líneas generales de la reestructuración de las actividades del sector y además marcaba como objetivo el 12% del consumo de energía primaria proveniente de fuentes renovables en el año 2010. Esta ley también contenía un régimen especial de apoyo a estas tecnologías basado en un sistema de primas. Este objetivo fue un gran estimulo para el incremento de la participación de las renovables en la estructura de generación del país, la cual pasó de representar el 2% de la potencia total instalada en 1998 al 29% en 2012. Teniendo en cuenta la situación de las renovables en España a lo largo del periodo de reestructuración de su sector eléctrico, en esta tesis se propone averiguar el impacto económico de estas fuentes de energía en el precio final medio de la energía eléctrica durante este período. La herramienta seleccionada ha sido el análisis comparativo en entornos similares para algunas variables y en entornos muy diferentes para otras, lo cual debe permitir identificar el efecto de las variables de interés en el precio final medio de la electricidad en el Reino Unido, California y Brasil junto con España. En esta tesis se ha utilizado el precio final medio de la electricidad como parámetro para valorar los efectos de la reestructuración del sector eléctrico en lugar de utilizar el precio de la electricidad para consumidores domésticos o industriales, debido a que el objetivo era analizar el comportamiento de esta commodity en el país como un todo y no para una determinada clase de consumo. El precio final medio de la electricidad se determinó considerando los costes reales de la energía eléctrica en cada ejercicio. Para comparar este precio entre los distintos países se utilizó el purchasing power parity (PPP) como factor de conversión del cambio de divisas para convertir los precios nominales a dólares internacionales, además de ecualizar en el proceso el poder de compra de los países considerados, eliminando las diferencias de nivel de precios entre ellos. Para el análisis propuesto se han recopilado datos procedentes de distintas fuentes, abarcando un horizonte temporal de unos 30 años. La localización, verificación y homologación de estos datos procedentes de fuentes muy diversas es uno de los aspectos novedosos y fundamentales de esta tesis. A partir de estos datos se elaboraron las curvas de precio final medio de la electricidad y de las variables que podían tener alguna influencia en éste, para entonces establecer correlaciones entre el precio y cada variable. La hipótesis de partida era que el aumento de generación renovable en España había tenido una repercusión mensurable en los precios, mientras que en los países comparados esta repercusión había sido insignificante, con lo cual, a partir del análisis comparativo de las correlaciones encontradas entre las curvas de precio final medio de la electricidad y las curvas de las variables identificadas, se segrega la influencia específica de las renovables en la reestructuración del sector eléctrico español. / Martinez Castor De Cerqueira, M. (2014). Repercusión de las energías renovables en la liberalización del sector eléctrico en España: análisis comparativo incluyendo Reino Unido, California y Brasil [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/43592 / TESIS