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Abstract. For Electric Power System safety and stable operation, planning and analysis by using simulation environments are necessary. An important point for frequency stability analysis is, on one hand, an adequate representation of Load-Frequency Control (LFC) loops and, on the other hand, the design of advanced control strategies to deal with the power system dynamic complexity. Therefore, in this paper we propose to represent the group turbine/penstock, found in hydropower plants, in a Piecewise Affine (PWA) modelling structure. Based on such modelling, we also propose the use of a Hybrid Model Predictive algorithm to be use as a control law in LFC loops. Among the advantages of this PWA representation is the use of this model in the controller algorithm, thereby improving the Load-Frequency Control performance. Simulation results, on a 200 MW hydropower plant compares the performance of predictive control strategy presented with the classical PID control strategy in an isolated condition.

PMV-MBPC Algorithms for Thermal Comfort: An Application to a Test-cellThe present paper is focused on thermal comfort control problem for building occupants. Thermal comfort is a concept difficult to define and, here, the PMV (Predicted Mean Vote) index is used by means of two predictive control strategies, characterized by having terminal constraints, called here PMV-MBPC (PMV Model Based Predictive Controller). The first thermal comfort control strategy is based on generating a temperature set-point signal that optimizes the building (single zone) internal PMV value. The second one includes the PMV model in the controller prediction computations, generating a non-linear PMV model having Wiener structure. Results related to closed loop system stability are proposed. In this context, an environment for control systems tests is described and the first approach is then implemented in real time using an oil-heater and this environment. Experimental results illustrate the thermal comfort control system performance. Additionally, simulation

Hydroelectric plants are the main sources of energy in Brazil. For their correct functioning is essential to maintain the stability of the system; one way to ensure this is through the stability of the frequency, via the speed controller for such a task. Proportional-integral (PI) type controllers are used, in order to achieve desired performance and stability. To find suitable gains of the controller, multi-objective control techniques are applied, because their usefulness to represent the trade-off between conflicting objectives. In this work we use such techniques to evaluate the trade-off between load rejection and robustness of the speed controller. For this different PI controls were tested for a plant representing the hydraulic mesh in order to validate its utility. Resumo: Usinas hidrelétricas são as principais fontes geradoras de energia no Brasil. Para o correto funcionamentoé essencial manter a estabilidade do sistema. Uma maneira de garantir estaé através da estabilidade de frequência, a qualé feita através do regulador de velocidade que nada maisé que um controlador para a malha hidráulica. Desta forma, o controlador do tipo proporcional-integral (PI)é utilizado a fim de obter um desempenho e estabilidade desejados. Para encontrar os ganhos do controlador são aplicadas técnicas de controle multiobjetivo, pois estas se mostramúteis pela capacidade de representar o câmbio entre os objetivos conflitantes. Neste trabalho utilizam-se tais técnicas para avaliar o trade-off entre rejeição de carga e robustez do regulador de velocidade. Para tal, diferentes controles PI foram testados para uma planta que representa a malha hidráulica de um regulador de velocidade, a fim de validar sua utilidade.