Validation of hydraulic modeling

Introduction

A validation of the hydraulic modules has been performed in collaboration with “Entreprises Electriques Fribourgeoises” –EEF–; public utilities of Canton Fribourg in Switzerland. Three Hydroelectric power plants have been modeled using SIMSEN-Hydro. All the hydraulic installations feature upstream reservoir, gallery, surge tank with variable section, penstock, manifold and Francis turbines. Measurements of emergency shutdown were provided by EEF for the three power plants.

The comparison is done for the Francis turbine inlet pressure. Due to circuit breaker tripping of the units of concerns, the turbines go to a runaway speed that is reduced by the guide vanes closure. From this maneuver, results a quick pressure rise at turbine inlet due to waterhammer effect. A slow pressure rise related to surge tank mass oscillation occurs. The slow closure of the protection valves induces small pressure fluctuations late after the first waterhammer effect.

Simulation cases
Main results
Simulations performed for the three test cases present good agreements with measurements. Especially, waterhammer and mass oscillation effects are properly reproduced. In addition, they demonstrate the flexibility of the software for modeling non conventional modules. Using the parameterization approach allows modeling of elements such as emergency bypass for Broc power plant and differential surge tank for Châtelot power plant.

 
Realized in collaboration with Entreprises Electriques Fribourgeoises (Switzerland)
 
http://simsen.epfl.ch
 
Chemin des Champs-Courbes 1
CH-1024 Ecublens
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