An efficient method for optimal location and sizing of fixed and switched shunt capacitors in large distribution systems

This paper proposes a computationally efficient methodology for the optimal location and sizing of static and switched shunt capacitors in large distribution systems. The problem is formulated as the maximization of the savings produced by the reduction in energy losses and the avoided costs due to investment deferral in the expansion of the network. The proposed method selects the nodes to be compensated, as well as the optimal capacitor ratings and their operational characteristics, i.e. fixed or switched. After an appropriate linearization, the optimization problem was formulated as a large-scale mixed-integer linear problem, suitable for being solved by means of a widespread commercial package. Results of the proposed optimizing method are compared with another recent methodology reported in the literature using two test cases: a 15-bus and a 33-bus distribution network. For the both cases tested, the proposed methodology delivers better solutions indicated by higher loss savings, which are achieved with lower amounts of capacitive compensation. The proposed method has also been applied for compensating to an actual large distribution network served by AES-Venezuela in the metropolitan area of Caracas. A convergence time of about 4 seconds after 22298 iterations demonstrates the ability of the proposed methodology for efficiently handling large-scale compensation problems.

Optimal scheduling of a renewable micro-grid in an isolated load area using mixed-integer linear programming

In the energy management of the isolated operation of small power system, the economic scheduling of the generation units is a crucial problem. Applying right timing can maximize the performance of the supply. The optimal operation of a wind turbine, a solar unit, a fuel cell and a storage battery is searched by a mixed-integer linear programming implemented in General Algebraic Modeling Systems (GAMS). A Virtual Power Producer (VPP) can optimal operate the generation units, assured the good functioning of equipment, including the maintenance, operation cost and the generation measurement and control. A central control at system allows a VPP to manage the optimal generation and their load control. The application of methodology to a real case study in Budapest Tech, demonstrates the effectiveness of this method to solve the optimal isolated dispatch of the DC micro-grid renewable energy park. The problem has been converged in 0.09 s and 30 iterations.

Adaptive tackling of the swinging problem for a 2 DOF crane – payload system

The control of a crane carrying its payload by an elastic string corresponds to a task in which precise, indirect control of a subsystem dynamically coupled to a directly controllable subsystem is needed. This task is interesting since the coupled degree of freedom has little damping and it is apt to keep swinging accordingly. The traditional approaches apply the input shaping technology to assist the human operator responsible for the manipulation task. In the present paper a novel adaptive approach applying fixed point transformations based iterations having local basin of attraction is proposed to simultaneously tackle the problems originating from the imprecise dynamic model available for the system to be controlled and the swinging problem, too. The most important phenomenological properties of this approach are also discussed. The control considers the 4th time-derivative of the trajectory of the payload. The operation of the proposed control is illustrated via simulation results.

Multiple Roots of Systems of Equations by Repulsion Merit Functions

In this paper we address the problem of computing multiple roots of a system of nonlinear equations through the global optimization of an appropriate merit function. The search procedure for a global minimizer of the merit function is carried out by a metaheuristic, known as harmony search, which does not require any derivative information. The multiple roots of the system are sequentially determined along several iterations of a single run, where the merit function is accordingly modified by penalty terms that aim to create repulsion areas around previously computed minimizers. A repulsion algorithm based on a multiplicative kind penalty function is proposed. Preliminary numerical experiments with a benchmark set of problems show the effectiveness of the proposed method.

Relatório de estágio de qualificação profissional (Fase intercalar do estágio)

Relatório EPE - Relatório de estágio em Educação Pré-Escolar: O presente relatório de estágio emerge da prática pedagógica supervisionada na educação de infância inserida no curso de mestrado de educação pré-escolar e ensino do primeiro ciclo do ensino básico. Esta foi desenvolvida no jardim de infância da Escola Básica de Monte Aventino que integra o Agrupamento de Escolas António Nobre. O estágio formativo efetuado teve como principal intenção o desenvolvimento de competências profissionais associadas à capacidade de reflexão sistemática antes, durante e pós-ação tendo em vista o desenvolvimento de uma ação educativa baseada na investigação de práticas e na co-construção de saberes profissionais. No sentido de alcançar as competências estabelecidas e de direcionar a prática educativa para os interesses e necessidades das crianças foram exercidas várias etapas cíclicas do processo educativo como a observação, planificação, reflexão e avaliação. Deste modo a metodologia eleita para o exercício deste ciclo espiral assentou na investigação-ação uma vez que esta permite indagar sobre as práticas desenvolvidas tendo em vista a sua reestruturação voltada para as carências demonstradas. Como estratégia de formação, esta metodologia também possui grandes potencialidades sendo que foram igualmente utilizados procedimentos como reflexões individuais, narrativas colaborativas e guiões de observação orientados para o favorecimento da investigação individual e colaborativa das práticas exercidas em díade e tríade de formação. O desenvolvimento das diversas ações referidas conduziu ao alcance das competências enunciadas que confluíram na formação do perfil profissional da mestranda capaz de criar um integrado do currículo, recorrer ao exercício das etapas do processo educativo assim como à organização do ambiente educativo.