Study Of Ventilation Cooling System And The Stator Temperature Field In Large Synchronous Generator

The development of high-parameter, large-capacity synchronous generatorshas become the trend that China’s power industry expands gradually, the loss ofthe structures in generators has increase with the capacity larger. Therefore, It isimportant factor for designing and developing the larger synchronous generatorsthat the ventilation cooling effect should be improved, the more heat generatedfrom the loss should be taken away, the high temperature rise should be declinedin the normal operation.In this paper, as a330MW water-hydrogen-hydrogen cooled turbo-generator,the ventilation network model of half axial section generator was built accordingto the complex ventilation system characteristic and the actual structure size, thetotal flow、the flow of the ventilation ducts and wind chambers、the nodepressure were obtained with the fluid network method. As can be seen from thecalculated results, the flow distribution of each ventilation ducts is reasonable,and the calculated accuracy can be verified by calculating the temperature of thecooper shield in the stator end. In addition, the distances were adjusted, includingthe radial distance of the air space diaphragm and the rotor ring, the axialdistance of the wind seperate diaphragm and the press plate, the flowing area ofthe copper shield and the press plate. The change of the flow and the nodepressure of the ventilation system was compared with the original program, theventilation system characteristic and the cooling effect of the end structures wereanalysed, which provides the reliable basis for designing the large turbo- generator ventilation system structure.In addition, as a250MW,68.2rpm air-cooled hydrgenerator example, thetemperature field model including half a core section along the axial, a tooth anda slot along the circle was calculated with the equivalent thermal network methodand the finite volume method. Considering eddy current loss of each strand in thetop and bottom bar without the rotation effect of the rotor, the boundaryconditions in the solving regions are given through the calculations on thetemperature rise of the air gap and the flow rate of the stator ventialtion duct.Compare to the position of the local maximum temperature confirmed with twodifferent methods, the solution time and solution scale with two methods areanalysed. Compare the calculations with the experimental tests, the accuracy andeffectiveness with two methods are validated, it is important practicalsignificance to design and develop the larger capacity synchronous generator.