Physical modelling of transients in hydropower plant tunnel systems

Livia Pitorac, Leif Lia, Kaspar Vereide

Being topical is a challenge that hydropower plant developers are constantly encountering nowadays. The power market is constantly changing in order to accommodate renewable energies, and hydropower has to do accordingly. Moreover, worldwide, development of large hydropower schemes is critizised from an environmental impact point of view. All these challenges need to be addressed and solved, and redesigning old hydropower plants to pump storage plants could be one solution. In most Norwegian hydropower tunnels, there is a number of surge tanks, brook intakes and unplugged adits, which gives a higher complexity to the hydraulics system. The scope of this master thesis is to analyze the effect of an unplugged adit to the stability of hydraulic system of a hydropower plant. In the specific case of an adit outlet connected to a reservoir, the behavior of the mass oscillations is very dependent on the reservoir level, thus analyzing how these two components are connected is of interest. In the work, physical modelling of mass oscillations is to be performed, using a hydraulic model developed at the Hydraulic Laboratory, at NTNU. The topic is part of a larger project on physical modelling of reconstruction of existing hydropower plant to pumped storage plants.