Experimental study on load rejection process of a model tubular turbine

To obtain the dynamic parameters variation characteristics of a model tubular turbine during the load rejection process, a model test method was designed and carried out in this paper. Firstly, the model test system, the test method and the model tubular turbine parameters were introduced. Then, the experiments of different schemes were performed and the results were analyzed. Evidently, the closing rules of guide vanes and runner blades have influence on the quality of transient process. When the guide vanes undergo linear needle closure law, the effect of prolonging the blade closing time on reducing the maximum speed appreciation and the maximum reverse water thrust is obvious, and when the guide vanes is closed in two stages, the longer the blade closing time, the lower the maximum reverse hydraulic thrust value. With the same closing law, the segmental closure law with guide blade first fast and then slow is more obvious than the linear needle closing law in reducing the maximum reverse water thrust, and the selection of closure segment point of guide vanes has a certain effect on the appreciation of the maximum rotating speed. Thus, the model test method could be used in transient operation improvement at hydropower plants.