AUTHOR=Zhou Ye , Ma Jianfeng , Cao Dengfeng , Wu Lielong 

TITLE=Startup Process Optimization of Hydropower Unit Based on Stress Measurement of Francis Turbine Runner

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.885634

DOI=10.3389/fenrg.2022.885634

ISSN=2296-598X

ABSTRACT=The energy efficiency characteristics of the turbine, the cavitation performance of the runner, and the operation stability of the unit are the three major concerns of the hydropower field, the latter two factors lead to units’ cavitation and stability problems under some operation conditions, and fatigue failure of runner blades, which are the main causes of structural and mechanical failure for hydropower units. In this paper, three conventional unit start-up processes are introduced, and combined with the optimal impulse control strategy, an optimized unit startup method is proposed. As the optimal guide vane opening adjustment setting value being obtained by solving the planned startup control strategy, the 3D modeling and CFD simulation are carried out, then the equivalent stress characteristics are obtained by finite element calculation when the unit is running from startup to no load at rated speed on three different startup modes. At last, the dynamic stress tests of the runner blade are performed at the hydropower station by using the wireless acquisition and transmission technology, and the peak value and characteristics of the dynamic and static stress of the blade under different startup processes are obtained. In which, the validity of the model analysis is proved with the comparison between the simulation calculation and the measured results, and the effectiveness of the start-up control strategy is proved by combining the runner blade dynamic stress simulation, calculation, and the field dynamic stress test results. The optimization method of the startup process proposed in the paper can alleviate the abnormal vibration of the unit and provide a basis for the long-term stable operation of the hydropower unit.