Study On Large Fluctuation Transition Process Of Hydraulic Turbine In XW Hydropower Station

As an important carrier of the sustainable development of economy and culture,energy is facing challenge such as resources exhaustion, efficiency promotion,energy-saving and environmental protection and so on. Electric power is one kind of important energy in our daily life and production. with the rapid development of national economy, the demand and consumption of electric power from various industries is becoming bigger and bigger. Increasing depletion in the energy and increasingly serious environmental damage today, developing and utilizing the renewable resources has become a world focus. hydropower is more Environmentally friendly and easier to develop and utilize, and it has lower operation cost compared with coal power and nuclear power. Thus it plays an important role in our country’s and even the world’s energy system.Many accidents happened during the hydropower station operation. many accident examples proved that accidents often occurred in the hydraulic transition process no matter it is dam type hydropower station, diversion type hydropower station, pump station or Pumped Storage Power Station.accidents usually lead to load rejection of the units, then comes the rise of rotating speed, the gates close and the units go back to its load speeds. During the process described above, the great changes of load will cause radical changes of the system frequency, therefor, The stability of the control system will be affected, in addition, the rise of pressure will result in the damage of the tube, when the rotating speed increases, the unit strength will be affected. When the inlet pressure of the draft tube is too low, water cut-off may happen, then, water that left the runner would flow back and the impact of water would cause raising-turbine accident. So research on transiting process of acute fluctuation of hydraulic unit is meaningful.Taking a certain large hydropower station in southern China as an example, this thesis has done some research on transiting process of acute fluctuation of hydraulic unit. The main contents in this thesis are as follow:(1)、Pressure change curves and speed change curves simulated in Water Diversion System shows the maximum pressure at the end of the spiral case, the maximum speed, the minimum negative pressure at the inlet of tail water tunnel.(2)、The reliability of the simulation results are Verified by the comparison between measured results and simulation results,as well as matalab simulation results and the commercial software simulation results, and real-time closing law of guide vane is to be found.(3)、Theoretical Analysis and study on the influence of the friction on transiting process of acute fluctuation of hydraulic unit has been presented. By comparing the simulation results of large oscillation transient process of one hydraulic unit while friction is considered with the results of that while friction is not considered, the validity of the theory has been proved.