NUMERICAL SIMULATIONS OF HYDRAULIC TRANSIENTS IN HYDROPOWER PLANT JAJCE II

Hydraulic transients in hydropower plant Jajce II (Bosnia and Herzegovina) were simulated with ID unsteady pipe flow model. High accuracy of the model was accomplished with the use of non-conservative formulation of an unsteady pipe flow model incorporating a modified instantaneous acceleration-based unsteady friction model and second order flux limited numerical scheme. In order to apply the model, complex dual surge tank geometry needed to be represented with a unified surge tank. The numerical model was validated against the measured data on three simulation scenarios, defined with different turbine discharge reductions. Simulation results show a very good agreement between the computed and measured piezometric heads, both in amplitude and frequency of the oscillation.