Dynamic evolution of a bulb hydroelectric generating unit considering effects of the blades

Abstract The stability problems of the hydroelectric generating unit caused by the vibration of the runner blades have been gradually exposed in the long-term operation, especially in the hydropower stations equipped with the bulb turbine. However, in the previous studies, the effects of the blades were not considered. Aiming at these problems, this research will be focused on studying the dynamic characteristics of the bulb hydroelectric generating unit in consideration with the effects of blades. Firstly, a novel continuum shaft system model of the bulb hydroelectric generating unit is originally established considering the effects of the blades. Meanwhile, the rationality of the novel model is verified by comparing with the field test data. Then, the dynamic evolutions of the shaft system with and without blades are contrastively analyzed and discussed with the changing of the runner mass eccentricity, the seal gap, the rotational speed and the exciting current. Fortunately, some critical values and stability evolution characteristics of the shaft system are obtained. In addition, the effects of the blades are also found. More importantly, these results could provide a reference for the safe operation of the hydropower stations.