NUMERICAL ANALYSES OF HYDRAULIC NETWORKS OF COOLING WATER SYSTEMS OF GENERATING UNITS OF HYDROPOWER PLANTS – CASE STUDY OF HPP VRLA 1

AUTHOR(S) / АУТОР(И): Aleksandar Petković, Jovan Ilić, Nikola Tanasić

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DOI: https://doi.org/10.46793/EEP25.192P

ABSTRACT / САЖЕТАК:

Cooling water systems of generating units (turbine-generator sets) are one of the most important auxiliary systems at hydropower plants. Their function is to assure prerequisites for unrestricted long-term operation of the generating units under all exploitation circumstances (i.e. number of generating units in operation, their operating power, during all seasons of the year). For each possible conceptual solution of the cooling water systems (joint, group, individual) and each possible manner of providing water streaming (pumping from tailwater, intaking from turbine spiral casings followed by ejector jet pumping or by pressure reducing) pipe networks of these systems are structurally and hydraulically complex, branched and looped, arrangements. Aside of topological complexity, these systems are characterized by presence of various constellations of exploitation regimes and numerous items of equipment (pumps, filters, regulating/shut-off valves, heat exchangers, measuring devices), fittings (bends, branches, converging/diverging pieces) and pipe reaches, which technical characteristics are to be comprehensively selected (varied and finally adopted) within design stage. For that reason, these systems cannot be easily and conveniently analyzed by “traditional” methods (analytical and/or graphical matching of pump and pipeline operating curves) due to demanding and error-prone efforts. In such conditions, it is much more expedient to apply numerical tools, i.e. softwares with graphic user interface for easy determination of the system topology and entering/modifying of the structural and hydraulic characteristics of the system elements, with clear overview of the obtained results (i.e. flow and pressure distribution) at any point of the system. Softwares for numerical analyses of hydraulic networks have been used in worldwide practice for more than 30 years. The paper presents the results of conducting numerical analyses of cooling water systems in EPANET software for the case study of HPP Vrla 1 (of 4 x 14 MW installed output).