Aleksandar Gajic

Smart design requires updated design and analysis guidelines

This paper reviews several cases where there is an obvious and important margin between the ideal of smart design and the practical reality which often makes due with obsolete guidelines, outdated recommendations and leads to expensive maintenance troubles. Stated alternatively, this paper is a plea for an attempt to better integrate high technology, experience, knowledge and economics so that both owner and human interests can be better supported and protected. To this end, several well-known plants (Sayano-Shushenskaya, Grand Coulee, Niagara Falls, Richard B Russell, Iron Gates 2, Jenpeg, Bajina Basta, Zvornik, to name a few) have been briefly analysed to clarify the crucial need for updated approaches. Of course, whether the plant is large or small, designing, constructing, operating and updating hydropower plants is a complex set of tasks. Any hydroelectric installation, as a rule, should be designed in several stages. At each stage, entire project documentation should be reviewed by independent reviewers. Reducing the number of analyses, or limiting their scope, with no clear justification except for an attempt to save a little on cost upfront, or worse yet, neglecting the design procedures, can put a project at risk. For a variety of reasons the continuity of knowledge and experience has been lost nearly everywhere. The paper argues that an organized and multidisciplinary transfer of experience is a priority task to be undertaken by the electricity sector. There is a clear need to plan, finance and implement various long-term initiatives; it is urgent that decisions to address this be made now to preserve the currently available knowledge and the almost 200-years of project experience.

Hydraulic Oscillation Analysis Using the Fluid-Structure Interaction Model

The paper presents a fluid transients analysis in hydraulic systems including fluid-structure interaction (FSI). The method is based upon an improved model, that takes into account gravitational and hydraulic resistive forces. The results of calculation applying the FSI model are compared to results obtained by simplified models and to those recently published.

Design Challenges in Hydropower Systems: Trade-offs and Difficulties in Operation

Hydraulic systems experience a variety of challenging conditions including hydraulic transients and oscillations. A long list of complex causes -- including extreme pressures and resonance -- can threaten power plants: the litany of failure is both long and painful, but also instructive. In fact, it is estimated that more than 50% of hydroelectric plants worldwide and other energy-related systems such as water transporting plants, water cooling system in nuclear and other thermal plants, oil pipelines, experience serious trouble or suffer severe operational constraints. We contend here that at least one problem is the presumption that comes from thinking that this is what a well known and used technology, and thus we have grown inattentive. Moreover, we argue that a vigorous and reflective design and review procedure, diligently applied, would be a great assistance not only for the quality of projects but also to assist the education of the next generation of experts. Specifically, we believe that an appropriate design, review, and trial operation procedure could have prevented many recent accidents and troubles.