Analysis of safety margin for pump-turbine “S” characteristics of Pumped-storage Power Stations

Abstract The pump-turbine is the “heart” of Pumped-storage Power Stations, and the “S” characteristics is an inherent characteristic of the routine Francis pump-turbine unit, which is an important factor affecting the safe and stable operation of the unit. There are three main methods for conducting research on the “S” characteristics: model testing, on-site testing, and CFD numerical simulation calculation. Based on the theoretical research of CFD numerical simulation calculation, this article compares and analyzes the results of model testing and on-site testing for specific practical cases, studies the differences between these two methods, and provides suggestions for the reasonable value of safety margin in the “S” area of the pump-turbine based on engineering practice, providing reference for the design of new or renovated power stations and the hydraulic optimization of pump-turbines.