INVESTIGATION OF OSCILLATORY PROBLEMS OF HYDRAULIC GENERATING-UNITS EQUIPPED WITH FRANCIS TURBINES

In the present paper a method is presented for the study of oscillator y problems of hydraulic generating units equipped with Francis turbine s. The accurate equations of the turbine are implemented for the simul ation, taking into account water hammer effect. Partial derivatives of turbine flow rate and torque with respect to head and gate opening ar e deduced from real measurements for the whole loading range. Speed go vernor dynamics are fully simulated, and the influence of torsional vi brations Is studied. The vibration response of the unit to draft tube surges is investigated and the risk of excessive oscillations is evalu ated. The approach was developed for diagnosis of excessive vibrations of Kastraki hydro power station in Greece.