Parametric Analysis of Water-Hammer Effects in Small Hydro Schemes

Abstract

In small hydro schemes, when equipped with small inertia turbines, the parameterization of water-hammer effects might allow a better characterization of the dynamic behavior of these turbomachines, assisting in the choice of the most appropriate solution. This is particularly important when there is a lack of turbine characteristic curves. A novel technique, based on a dynamic orifice concept, is presented herein. This technique enables the simulation of the turbine operation during both steady-state and transient conditions, which allows a reliable evaluation of various scenarios with different characteristics, essential for design purposes. This type of analysis establishes the interaction between the powerhouse and the hydraulic circuit by means of the characteristic parameters of each component. The most severe hydrotransients occur during extreme operating conditions, such as full-load rejection and turbine stoppages, particularly when the small hydro is installed in hydraulic systems with high head or long pipeline length.