The Pelton turbine is a hydraulic prime mover that uses a special water guiding mechanism to draw a free jet with kinetic energy, rush to the runner bucket, and make the runner rotate to perform work, thereby completing the conversion of water energy into mechanical energy. The Pelton turbine is suitable for high-head, low-flow power stations. It converts the water from the pressure pipeline into a high-speed jet after passing through the nozzle, and tangentially impacts the runner, pushing the runner to rotate, thereby driving the generator rotor to rotate and generate electricity. In the Pelton turbine, based on the relative position of the working jet and the runner and the number of workmanship, it can be divided into a chopper turbine, an inclined jet turbine, and a cross-flow turbine.
Theoretical analysis proves that the efficiency is highest when the circumferential velocity at the pitch circle of the bucket is about half of the jet velocity. When a load of this kind of turbine changes, the direction of the water inlet speed of the runner does not change. In addition, this kind of turbine is used in high-head power stations. The head change is relatively small, and the speed change is not large, so the efficiency is less affected by the load change, the efficiency curve is relatively flat, with the highest efficiency exceeding 91%.
With the in-depth development of hydraulic resources, there are many high-drop watersheds that need to be developed, so Pelton turbines have become the first choice. The Pelton turbine has the following advantages:
1. Adapt to the situation where the ratio of flow to the head is relatively small.
2. The weighted average efficiency is very high, and the efficiency is very high in the entire operating range. In particular, bucket-type turbines are now advanced and can achieve an average efficiency of more than 91% in the load range of 30% to 110%.
3. The ability to adapt to changes in water head is relatively strong
4. It is also very suitable for pipes with a large ratio of water head.
5. The amount of excavation is small.
Using Pelton turbines to generate electricity, the output range can be from 50kW to 500MW, which can be applied to a larger head range of 30 meters to 3000 meters, especially in the high head range. Other types of turbines cannot be applied, and there is no need to build dams and no downstream draft tube. The construction cost is only a fraction of that of other types of hydroelectric generating units, and the impact on the natural environment is also very small. Since the runner runs in the runner chamber under atmospheric pressure, it is possible to omit the demanding requirements of pressure-flow passages, sealing, etc., widely used in high working conditions and smooth changes are another reason for its charm. Due to the above-mentioned advantages, the development theme of Pelton turbine units is attracting worldwide attention. The Pelton turbine can give full play to its advantages of simple structure, small runner diameter, and high efficiency, greatly reducing power station investment and saving secondary resources, and the success of large-scale Pelton turbine development will create great economic benefits.