An on-line monitoring method for the flow excitation in francis hydraulic turbine based on dynamics

Abstract

During the operation of hydraulic turbine, the vibration often exceeds the standard due to flow excitation, which affects the safe and stable operation of the hydraulic turbine. In this paper, an on-line monitoring method for the flow excitation in Francis hydraulic turbine is proposed based on the dynamic characteristics of Francis hydraulic turbine. Firstly, based on the flow excitation characteristics in Francis hydraulic turbine and the dynamic equation of main shaft system, the internal relationships between the dynamic response of turbine bearing and the flow excitation in the Francis hydraulic turbine are clarified. Secondly, according to these relationships, a method based on wavelet transform (WT), particle swarm optimization (PSO), and variational mode decomposition (VMD) is proposed for extracting the flow excitation features in Francis hydraulic turbine. Then, by this method, the flow excitation features are acquired. Based on the obtained flow excitation features, the flow excitation can be monitored on-line. Finally, the proposed on-line monitoring method for the flow excitation in Francis hydraulic turbine is verified by experiments. Based on the results, the flow excitation components in the signal extracted by this method are about 35 % more than those extracted by the previous methods. The results show that the on-line monitoring method proposed in this paper is convenient and effective.

Application of Image Processing Sensor and Pattern Recognition in Detection of Bearing Surface Defects

“…The results show that the algorithm for feature extraction has certain value and plays a certain role in promoting the self-energy of detection [7]. Li, Z. and others have conducted preliminary discussion and research on online bearing size detection based on machine vision and designed a detection system on the flow production line [8]. The system requires the bearing to move on the conveyor belt according to a certain beat, the image capture is synchronized with the production line, and the images are captured at the same time.…”