Hydro generator is composed of rotor, stator, frame, thrust bearing, guide bearing, cooler, brake and other main components (see Figure). The stator is mainly composed of frame, iron core, winding and other components. 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 water turbine generator is generally cooled by closed circulating air. Super large capacity units tend to use water as cooling medium to directly cool the stator. If the stator and rotor are cooled at the same time, it is a double water internal cooling wheel generator set.
In order to improve the single unit capacity of hydro generator and develop to giant unit, many new technologies are adopted in structure in order to improve its reliability and durability. For example, in order to solve the thermal expansion of the stator, the stator floating structure and inclined support are used, and the rotor adopts the disc structure. In order to solve the looseness of stator coil, cushion strip under elastic wedge is used to prevent insulation wear of wire rod. Improve the ventilation structure and reduce the wind loss and end eddy current loss to further improve the unit efficiency.
With the development of pump turbine manufacturing technology, the speed and capacity of generator motor are also increasing, developing to large capacity and high speed. The built energy storage power stations equipped with large capacity and high-speed power generation motors in the world include dinowick pumped storage power station (330000 KVA, 500r / min) in the UK.
The manufacturing limit of generator motor can be improved by using double water internal cooling generator motor, and the stator coil, rotor coil and stator core are directly internally cooled with ionic water. The generator motor (425000 KVA, 300r / min) of lakongshan pumped storage power station in the United States also adopts double water internal cooling.
Application of magnetic thrust bearing. With the increase of generator motor capacity and speed, the thrust load and starting torque of the unit are also increasing. After the magnetic thrust bearing is used, due to the magnetic attraction opposite to gravity, the thrust load reduces the load of the thrust bearing, reduces the shaft surface resistance loss, reduces the bearing temperature, improves the unit efficiency, and reduces the starting resistance moment.
Post time: Nov-05-2021
