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In Brazil, the development of the dam engineering can be directly correlated to social and economic progress. Although fundamental, a dam construction and operation invariably involve some level of risk, which must be managed through different mechanisms and tools governed by appropriate laws. This paper aims to scrutinize the data contained in National Water Agency (ANA) reports, published annually following institution of the National Dam Safety Policy (PNSB), pertinent to dams accidents and incidents. This information was cataloged and analyzed in order to identify trends associated to types of accidents and incidents, dam component materials and entrepreneurs involved, as well as the disparities between data available from the different regions of Brazil. There is a lack of basic data in numerous reports, hindering more in-depth statistical analyses. The recurrence of this deficit was observed as well as the need to improve the methodologies used to apply the PNSB guidelines. [ABSTRACT FROM AUTHOR]

In this paper the design of power system stabilizers for small-signal stability using phasor measurements is considered. An approach based on optimal control with structural constraints is proposed to design a two-level control structure. Time delays are included in the design. The method is combined with order reduction to ensure faster convergence of the design algorithm and to facilitate the choice of the weighting matrices for damping inter-area modes. The control scheme is discussed and modal analysis and time-domain simulations of two Brazilian equivalent systems are performed to assess the control performance. The robustness to loss of communication links, topological changes, and variations of time delay is evaluated. [ABSTRACT FROM AUTHOR]