Influence of Runner Blade Angle Variations on Kaplan Turbine Transients.

On the occasion of commissioning of the Kaplan turbines of Villerest and Oz-en-Oisans, the influence of the variation of the blade angle on the transient states is analyzed by comparing computations and industrial tests. To take into account the movements of the sluice gates and propeller, the reduced characteristics are determined by double interpolation according to the distributor openings and blade angles. The numerical results obtained, in particular the variation in rotation speed, agree well with the test records: for slow blade closing and rapid blade opening, for nominal and partial powers and heads and for different speeds of operation of the distributor. The influence of the blade angle variation is therefore not negligible.