The thesis focuses on the water hammer phenomena in the hydraulic conduits of the Norwegian high head hydropower plant Tonstad and a potential discharge upgrade. The first part of the thesis describes physical background of the water hammer occurrence and the systems to control it in the hydraulic conduits of the power plant. The 1D-numerical software LVTrans for the numerical modelling of the hydraulic transients is described. The second part of the thesis shows results of the 1D-numerical simulations. Attention is devoted to the calibration of the model, which is performed in several steps. The friction in the pipes, the pressure relief valves and surge tanks are calibrated separately. The calibrated model is further used to investigate the influence of the increased pressure in the hydraulic conduits, in case of load rejection event due to power production upgrade. The power increase is reached with higher discharge in the power water way resulting in lower water level in the surge tanks. During these conditions, emergency closure with several governor settings and pressure relief valve settings is simulated.
|
