The hydro-generator is composed of rotor, stator, frame, thrust bearing, guide bearing, cooler, brake and other main components (see picture). The stator is mainly composed of a base, an iron core, and windings. The stator core is made of cold-rolled silicon steel sheets, which can be made into an integral and split structure according to the manufacturing and transportation conditions. The cooling method of water turbine generator generally adopts closed circulating air cooling. Large-capacity units tend to use water as the cooling medium to directly cool the stator. If the stator and rotor are cooled at the same time, it is a dual water internally cooled water turbine generator set.
In order to increase the single-unit capacity of the hydro-generator and develop into a giant unit, in order to improve its reliability and durability, many new technologies have been adopted in the structure. For example, in order to solve the thermal expansion of the stator, the stator floating structure, oblique support, etc. are used, and the rotor adopts the disc structure. In order to solve the loosening of the stator coils, elastic wedges are used to underlay the strips to prevent the insulation of the wire rods from wearing out. Improve the ventilation structure to reduce wind loss and end eddy current loss to further improve the efficiency of the unit.
With the development of water pump turbine manufacturing technology, the speed and capacity of generator motors are also increasing, developing towards large capacity and high speed. In the world, the built storage power stations equipped with large-capacity, high-speed generator motors include the Dinovic Pumped Storage Power Station (330,000 kVA, 500r/min) in the United Kingdom and so on.
Using dual water internal cooling generator motors, the stator coil, rotor coil and stator core are directly internally cooled with ionized water, which can increase the manufacturing limit of the generator motor. The generator motor (425,000 kVA, 300r/min) of the La Kongshan Pumped Storage Power Station in the United States also uses dual internal water cooling.
Application of magnetic thrust bearings. As the capacity of the generator motor increases, the speed increases, so does the thrust load and starting torque of the unit. After using the magnetic thrust bearing, the thrust load is added with the magnetic attraction in the opposite direction of gravity, thereby reducing the thrust bearing load, reducing the axial resistance loss, reducing the bearing temperature and improving the efficiency of the unit, and the starting resistance The moment also decreases. The generator motor (335,000 kVA, 300r/min) of the Sanglangjing Pumped Storage Power Station in South Korea uses magnetic thrust bearings.
Post time: Nov-12-2021
