Numerical analysis of water hammer and water-mass oscillations in a hydropower plant for the most extreme operational regimes

Abstract

Hydraulic transients analyses are necessary during the design stage of both new and refurbished hydropower plants (HPPs). In this paper, transients of specified most extreme operational regimes are investigated for a long derivation system, provided with a surge tank as well as pressure relief valves (PRVs) at the turbines spiral casing. The transients analyses are focused on water-mass oscillations and water hammer. Investigations for various exploitation regimes and different operating laws of the PRV's are adopted. Results are obtained by means of an original software developed for these analyses. The model was duly calibrated, and the results were compared with the results of the transient analyses from the original design phase of the existing HPP.