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April 15, 2020
The selection criteria of the hydropower plant's turbine is very important. The standard was formulated to better guarantee the use of equipment, and the handling of every detail is very critical. The editor of the construction network introduces you to the regulations on the selection of hydraulic turbines in hydropower plants.
1. The selection of unit capacity should be based on the determination of the total installed capacity of the hydropower plant, considering the proportion of the unit capacity to the total working capacity of the power system, the system load growth rate, the layout of the hydropower plant hub, the operation mode of the unit and the reservoir, and the parameters of the unit The rationality, technical level of unit manufacturing and transportation conditions are waited for, and different schemes are proposed, which are determined through technical and economic comparison. In the case of equivalent technical and economic indicators, larger capacity units should be used. The number of units is generally not less than two.
After the model of the turbine is selected, the rationality of the operation of increasing the generator capacity or increasing the power factor should be studied based on factors such as the turbine's operating characteristics and hydraulic kinetic energy characteristics.
2. The rated head (clean head) of the turbine should be selected reasonably according to the operation mode of the reservoir and the role of the hydropower plant in the power system. When the rated head is close to the minimum or maximum head of the hydropower plant, its economics and rationality should be demonstrated.
3. The choice of turbine should adopt reasonable specific speed according to the range of working head, and choose the runner with high average efficiency and good cavitation and stability.
According to the unit capacity, working head range, operation mode and the comprehensive characteristic curve of the runner model, choose the runner straight
The main parameters such as diameter, speed and suction height.
In the selection of turbine parameters, it is also necessary to consider the initial low-head operation of the hydropower plant and the special requirements of the water quality for the turbine.
4. The installation height of the turbine should be selected according to the technical and economic comparison according to the allowable suction height value of the turbine under various working conditions and the corresponding downstream tail water level. The downstream tail water level should be selected according to the conditions such as the operation mode of the reservoir, the output change range of the hydropower plant, the initial operation requirements of the hydropower plant, the installation cycle of the unit, and the changes in the downstream river channel.
5. The maximum flyaway speed of a mixed-flow or axial-flow fixed-paddle turbine should be determined according to the maximum net head of the turbine and the maximum possible opening of the guide vane. The axial flow paddle turbine should calculate the flying speed according to the flying coefficient when the association relationship is not damaged. In special cases, it can be calculated according to the flight coefficient in the case of failure of the association relationship.
6. When choosing a turbine, new achievements in turbine manufacturing should be considered, and the adoption of major new technologies (including type, structure, and materials) must be scientifically tested and generally subject to technical appraisal.
The turbine should have anti-cavitation measures. In hydropower plants with muddy rivers, the flow-through components of the turbines should also be subject to anti-wear measures, and should be structurally convenient for maintenance and replacement of vulnerable parts.
7. For the selected turbine, the manufacturer should obtain the efficiency guarantee, power guarantee, cavitation guarantee and stable operating range guarantee, as well as the technical data such as the comprehensive characteristic curve and operation characteristic curve of the turbine model. If necessary, the data provided by the manufacturer for the accurate calculation of the turbine transition process should also be obtained.
8. When the highest water head is less than 40m, reinforced concrete volute with wrap angle of 180 ° ～ 225 ° should be used. When the highest water head is 40m and above, a metal volute with a wrap angle of 345 ° should be used. If a reinforced concrete volute is used, there should be
Technical and economic demonstration.
Reinforced concrete volute should consider anti-seepage measures.
9. The type and size of the turbine volute and draft tube should be taken into consideration with the manufacturer's layout or other special requirements and agreed with the manufacturer. If necessary, it should also be determined through model tests.
10. The taper of the draft tube should be lined with metal. According to the technical and economic comparison, the elbow part of the draft tube can be metal lined or concrete elbow. The immersion depth of the upper edge of the curved draft tube outlet should not be less than 0.5m.