Research On Stability And Economic Operation Of Large Kaplan Turbine

In this paper,we studied the stability performance,vibration zone division method and economic evaluation method of large axial-flow Kaplan units based on stability test and efficiency test.Axial-flow Kaplan turbines are mostly used in the working conditions of large flow and low water head.They can form different combinations by adjusting the opening of guide vanes and the turning angles of blades,which can better adapt to the change of load and achieve a wider and efficient operation area.The poor coordination of Axial-flow Kaplan turbines will increase the vibration and limit the unit output.Therefore,it is of key significance to study the stability performance and energy characteristics of Axial-flow Kaplan Hydroelectric units through real machine test for ensuring the safe and stable operation of the same type of units and enhancing the economic benefits of the power station.This paper mainly includes the following aspects:(1)This paper analyzes the characteristics of Kaplan turbines and the operation indexes of hydropower units.We also clarifies the principle of real machine test and the association relationship of Axial-flow Kaplan turbines.(2)Based on the operating stability test on safety water head,we analyzed the stability performance of the Kaplan turbines in detail,and discussed the division principle of the vibration zone.By analyzing the test data and determining the characteristic value representing the vibration of the units,the vibration zone of the units is divided according to the changing trend of the turbine guide bearing run-out with the active power.The results show that the smaller the working head of the units is,the more the swing exceeding the standard area tends to the low-load operation area.With the increase of the water head,the load area of the units corresponding to the peak-to-peak water guide swing exceeding the standard tends to move up.The higher the water head is,the greater the minimum load required for the unit to maintain stable operation.For large axial-flow hydropower units,when they operate under high head and low load conditions,the monitoring of swing and vibration of the units should be strengthened.The relative efficiency of the unit is improved when it reaches the rated head,and its coordination relationship is gradually close to the optimal ratio.The closer the working head of the unit is to the rated head,the easier it is to maintain the optimal coordination relationship,ensuring stable operation.(3)Based on the efficiency test of the association,the energy characteristics of the Kaplan hydropower units are analyzed.The existing collaborative relationship is optimized by comparing with the original collaborative curve of the power station.Based on the relative efficiency method,the water consumption rate method is used to evaluate the economic performance of the Kaplan turbine,the standard water consumption rate is introduced to evaluate the overall economic performance of the same type of units and power stations.Based on the lowest water consumption rate under each head,the optimal economic operation area of the Kaplan hydropower units in a power station is divided.The economic benefits are evaluated by comparing the standard water consumption rates of multiple power stations.The results show that the theoretical and practical optimal association relationship is in good agreement under high water head conditions.Adjusting the unit according to the optimized association relationship curve can make the hydraulic turbine run in the highest efficiency area;Using the standard water consumption rate can quantify the economic performance of the power station,and guide the economic operation and improve the economic benefits of the power station.