A physics-based multi-regime approach for estimation of head losses in operating hydropower plants

In this paper, the problem of estimating head losses in the hydraulic feeding system of a hydropower plant is considered. Accurate head loss assessment is crucial for performance monitoring, efficiency optimization, and predictive maintenance of these critical energy infrastructures. To this end, a nonlinear state-space model based on fundamental physical principles is first established. Recognizing the challenges of observability with a full complex model, this paper proposes a multi-regime modelling strategy, where the full model is particularized into simplified forms suitable for different operational scenarios (normal operation, quasi-static conditions, and plant shutdown). This approach facilitates the estimation of specific head loss coefficients or their combinations. Various estimation techniques are then explored and applied to these models, primarily based on Kalman filters for state-observer approaches and direct least squares for regression-based methods, all integrating real-time measurements. The efficacy of these methods is validated through comprehensive simulations and tests using operational data collected from an industrial hydropower facility.