Study On The Transient Process Of Power Station By Impulse Turbine

With the rapid development of hydropower projects, there are lots of power stations built or to be built with the properties of high-head, low-discharge and long-conduit systems, such as Bradley, Sifangdong, Baishuihe secondary and Maxianpin power station etc. This kind of stations usually adopts water impulse turbines because of the limitations of water head, cavitation and friction. But owing to their special structures and running characteristics, impulse turbines usually bring special effects to hydraulic transients. So it is very significant to research the mechanisms on how the impulse turbines function during the transient process. This thesis will present a set of new theories and methods, mainly by establishing the equations of boundary, unit and governor, to give a solution on simulating the transient process by impulse turbines, which is also based on the mature simulation methodology for transient process by mixed-flow-turbines. The major contents are listed as follows:Chapter 1: Indicate the significance and objective of this paper, review the previous achievements of the transient process, impulse turbine and upper tank, and then present the study purpose of this paper.Chapter 2: Present the basic simulation methodology of transient flow and list all kinds of boundary conditions in the objective systems.Chapter 3: From the physical essences of deflector motions and the characteristic curves of impulse turbine, give the detailed deduction on new deflector formulas. And then, aiming at single-jet and multiple-jet impulse turbine models respectively, describe two sets of methods for large-wave-transient process, which can be verified by a practical example illustrated at the end of the chapter.Chapter 4: On the foundation of large-wave-transient theories, establish the theories for small-wave-transients by importing governor and unit motions equations. And then, through a practical example, give the discussions on the problems such as the influences on the small-wave-transients by deflector motions and how to adjust to jet numbers corresponding to the load changes etc.Chapter 5: Based on the previous fruits of this thesis and taking Maxianpin station as an example, demonstrate the functions of upper tanks in this kind of high-head and long-conduit stations by analyzing the calculation results of large-wave-transients, small-wave-transients and hydraulic perturbation.Chapter 6: Summarize the whole paper, and present the future research directions and emphasis.