Effect of Turbine Characteristic on the Response of Hydroturbine Governing System with Surge Tank

The water level fluctuation in surge tank causes low- frequency fluctuations of unit´s output power and frequency, which adversely affect the response of hydro turbine governing system. Turbine characteristic is one of the most important factors affecting unit´s power and frequency during the governing. In this paper, based on the linearized model, the effect of turbine characteristic on the response of the hydro turbine governing system with surge tank, especially on the low- frequency fluctuations of unit´s power and frequency, is studied by numerical simulation with a given case. From the research, the main parameters of turbine characteristic which affect the response of the system have been pointed out, and the variations of these parameters in the comprehensive characteristics curves have been studied. Furthermore, different types of turbines have been analyzed, the results indicated that: the impact of turbine characteristic of medium or high specific speed turbine on the response of the governing system is more adverse than that of the low specific speed turbine.