Stability of water-level controls in hydropower plants accounting for backlash, delays and instrumental errors

We discuss the stability of run-of-river (ROR) hydropower plants. Despite this problem has been tackled for a long time, the relevant literature usually disregards important mechanisms such as: (i) backlash in mechanical actuators and components, (ii) delays in data processing and transmission, (iii) measurement uncertainties occurring in sensors, (iv) finite velocity of actuators, and (v) pressure surges within the penstock and in the headrace tunnel. The aim of this paper is to show the relevance of these (nonlinear) mechanisms on the stability of water-level controls in ROR plants.