Influence of hydraulic turbine operation modes on the hydraulic vibration of pressurized conveyance system in hydropower station

The calculation formulas of hydraulic impedance of turbine are derived under tow turbine operation modes: one is constant guide vane opening and constant speed, the other is constant output and constant speed. The differences of hydraulic impedance between the tow operation modes are studied, and the effects on the hydraulic vibration characteristics of pressurized conveyance system in hydropower station is disused through theoretical analysis and numerical calculation. The investigation shows that the positive or negative of the attenuation factors of system depends on the positive or negative of the hydraulic impedance of turbine, and the parity of the frequencies of the system depends on the hydraulic impedance of turbine, too.