Influence Of Hydraulic Excitation On Dynamic Characteristics Of The Main Shaft System Of Francis Turbine-Generator Units

For a long time, the intense vibration phenomenon of the Francis turbine generator units hovers around the hydropower stations all over the world, which seriously impacts the safe operation of the hydropower stations. Under the high water head,large flood discharge and intense electromagnetic, the vibration law of the units is mysterious and has not been solved throughly. With the incessant elevation of the water head and the Single Dynamo Capacity, the influence of hydraulic excitation on the dynamic characteristics of the main shaft system of the Francis turbine generator units are much more important. So the research of the characteristics of water flow in the Francis turbine and the influence of hydraulic excitation on the Francis turbine have important significance to improve the dynamic characteristics of the main shaft system of the Francis turbine generator units radically.In the past papers, the vibration eccentricity and turn eccentricity are not considered into the research of the water flow in the Francis turbine and the hydraulic excitation, but the vibration eccentricity and turn eccentricity are exist in the operation of the Francis turbine generator units, and they influenced the water flow in the Francis turbine and the hydraulic excitation, so it is necessary to consider vibration eccentricity and turn eccentricity into the research of the water flow in the Francis turbine and the hydraulic excitation.This dissertation make the research start from the water flow in the Francis turbine, through analysed the current velocity triangle at the import and exit of vane, obtain the current absolute velocity's component along the circle direction. When take vibration eccentricity and turn eccentricity into consideration, the water flow is different from before, and derivate the hydraulic excitation in the Francis turbine on the main shaft system of the Francis turbine generator units, the hydraulic excitation include the hydraulic parameters,electromagnetism parameters of generator and configuration parameters of the main shift system of the Francis turbine generator units, and the hydraulic excitation is not only correlative of electromagnetism torque, but also correlative of turn inertia of the Francis turbine generator units, which provide coupling dynamic analysis with reference. And consider the influence of the hydraulic excitation and other radial excitations on the main shift system of the Francis turbine generator units. Simulate and compute the unbalance steady-state responses at some especial positions of the main shift system.