High penetration of wind energy requires innovations in different areas of power engineering. Methods for improving wind energy and power system interconnection, control, and operation are proposed in this dissertation. A feed-forward transient compensation control scheme is proposed to enhance the low-voltage ride-through capability of wind turbines equipped with doubly fed induction generators. Stator-voltage transient compensation terms are introduced to suppress rotor-current overshoots and torque ripples during grid faults. A dynamic stochastic optimal power flow control scheme is proposed to optimally reroute real-time active and reactive power flow in the presence of high variability and uncertainty. The performance of the proposed power flow control scheme is demonstrated in test power systems with large wind plants. A combined energy-and-reserve wind market scheme is proposed to reduce wind production uncertainty. Variable wind reserve products are created to absorb part of the wind production variation. These fast wind reserve products can then be used to regulate system frequency and improve system security.

Orientador: Carlos Alberto de Castro Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-21T03:54:49Z (GMT). No. of bitstreams: 1 Tomiyama_EliasKento_M.pdf: 3080864 bytes, checksum: 7293fe7b3271c5c27e9b967c48a4e245 (MD5) Previous issue date: 2012 / Resumo: Esta dissertação de mestrado apresenta quatro metodologias de alocação de custos da transmissão: Pro rata (PR), Divisão Proporcional (PS), Zbus-médio (Zbus_AVG) e Nodal. Enquanto a primeira desconsidera o aspecto locacional e aloca os custos baseado apenas na quantidade de potência produzida pelos geradores e consumida pelas cargas, as últimas três levam em conta este aspecto, ou seja, as tarifas pagas por geradores e cargas dependem do seu ponto de conexão na rede elétrica. Através de simulações computacionais são levantadas várias situações de operação no sentido de avaliar a influência e as possíveis implicações de ordem regulatória, política, econômica e social de um país provocadas pela inclusão do aspecto locacional na definição das tarifas de uso do sistema de transmissão. Por fim, mostra-se a possibilidade de se considerar as tarifas pagas pelos agentes do sistema como um critério de decisão a mais no problema do planejamento da expansão da transmissão / Abstract: This dissertation describes four transmission cost allocation methodologies: Pro rata (PR), Proportional sharing (PS), Zbus-average (Zbus_AVG) and Nodal. While the first one disregards the locational aspect and allocates costs based only on the amount of power delivered by generators and consumed by loads, the last three ones take this aspect into account, i.e. charges are dependent on where generators and demands are connected in the network. Several computer simulations were made in order to assess the influence of the locational aspect into transmission pricing scheme and the results were used for a critical analysis, including political, regulatory, economic and social aspects. Finally, we discuss the possibility of using the fees paid by transmission system agents as an additional criterion for the Transmission Expansion Planning problem / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

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.

The thesis is focused on selected risks and theirs management in power sector. In introduction it is analysed power sector in the context of other energy commodities, hereafter it is analysed the approach to power price modelling. Furthermore are analysed the aspects of regulatory risk in Czech Republic. Finally it is evaluated the risk management system of a company in power- utility sector.