The design of hydraulic turbines has been primarily intended for operations close to their best efficiency point (BEP), and the off-design operations used to be rarely performed. Therefore, the electricity production for the power grid was stable, with the hydropower being the main tool towards this goal. However, the growing introduction of intermittent energy sources, such as wind and solar, has led to a less stable grid in recent years. Thus, hydropower has taken on a regulatory role instead, forcing it towards more operations at off-design conditions. Operations away from the BEP cause flow conditions that lead to the development of a rotating vortex rope (RVR) inside the draft tube. The presence of the RVR causes large pressure fluctuations that can damage the turbine and its components from increased wear. These periodic oscillations threaten the safety and sustained operation of the turbine over a long run since the turbine must be put to a halt for maintenance reasons. Furthermore, the hydraulic turbine experiences a decrease of efficiency as a result of RVR precession inside the draft tube.

The mitigation of the RVR has shown to be efficient with fluid injections inside the draft tube and rod protrusions inside the flow field. A downscale turbine of Porjus U9 at the John Fluid lab in Luleå University of Technology (LTU) investigates the RVR development and mitigation. The mitigation system is equipped with four 10 mm in diameter rods. The present work is aimed to develop and modify the necessary subsystems for the automation of the LTU test setup. So that RVR studies can be conducted without human intervention, therefore yielding results that can be validated through repeatability. The rig is operated through MATLAB: Simulink, while the signal digitalization and recordings of the RVR are done through LabVIEW. The rig is now operated so that various and numerous operation regimes can be investigated without human interaction by adjusting the flow rate, turbine speed and guide vane angles using PI-controllers inside Simulink.

The test rig is set up to be automatically operated. Specific set points regarding the flow rate from the pump, the turbine speed and the guide vanes are reached for a wide number of operation regimes. Moreover, test rig operations are stable, robust and the set points are reached within a short time. Rig operations for reduced speeds (n11) in the range of 100 to 135 rpm, guide vane angles in the range of 20° to 30° and pressure pulsations up to 70 Pa are collected automatically. The signals are exported to MATLAB to plot the hill chart. The turbine characteristics can be presented with respect to the parameters n11, guide vane angles and pressure amplitudes.