Increasing hydroturbine operation range and efficiencies using water injection in draft tubes

The project is a joint project between NTNU, a small business (Flow Design Bureau/ FDB) specializing in product solutions for increased hydropower performance and the operations responsible groups at a hydropower utility (Troms Kraft Produksjon/ TKP). The main objective of the project is to develop solutions that allow reaction type hydroturbines, such as Francis and Kaplan, to operate a low part loads without deleterious vibrations. If this objective is met a significant improvement in water resources management can be made. In addition a sucessful implementation can make run-off-river plant operate for longer periods of the year as well as allowing Francis turbines to act as spinning reserve in the electrical grid. Spinning reserve is a premisis for cogeneration between hydropower and new renewables. All of these factors is benefincial for the environement, economy of installation and the stability of the electrical grid. Noteworthy is the fact that the technology proposed in the project can easily b e fitted on existing power plants. At present a prototype installation is made at the Skarsfjord Powerplant outside Tromsø. This installation is considered used for applying developed control solutions. The project will also install a turbine model at th e Water Laboratory at NTNU. All parties of the project acknowledge that optimum solutions will have to be based on laboratory trials. Furthermore the sucess will also have to be based on a dedicated PhD candidate to the project. It's also acknowledged by all the parties that the basic understanding of the phenomenon of unsteadiness in draft tubes needs to be improved. For the commercial actors this is necessary for developing design tools that can enable successful implementation of the water injection s ystem in a commercial phase of the technology developmend. The project group is also confident that the proposed mix of academic/ industrial efforts is correct for the problem at hand.