Hydraulic Disturbance in Multiturbine Hydraulically Coupled Systems of Hydropower Plants Caused by Load Variation

This study focuses on the output variation and dynamic behavior of hydroturbines in a hydraulically coupled system under hydraulic disturbance. The theoretical formula predicting the output variation of operating turbines after hydraulic disturbance is presented, and the influential factors are discussed. To investigate the dynamic characteristics of the hydraulic turbine governing system (HTGS) and verify the accuracy of the formula, a mathematical model of the hydropower plant with multiple turbines sharing a common hydraulic system was established, and the transient process caused by partial load rejection was simulated on the basis of the operation of a real hydropower plant. The results show that the output variation of the operating turbine is in agreement with the theoretical formula, and the amplitude of overload is significant under the conventional regulating model, i.e.,opening control, in the low-head hydropower plants with long headrace tunnel during hydraulic disturbance. These methods and results will provide a theoretical basis for the safe operation and control of such hydropower plants.