Analysis And Calculation Of Multi-physic Fields For1000MW Hydro-generator

With the increase of the hydro-generator capacity, the electromagnetic and thermalloads of generators will increase. Therefore, it is important to study the heating andcooling problems of generators. The coupled problem of the electromagnetic fields,fluid fields and temperature fields for1000MW hydro-generator was mainly studiedin this paper using the numerical method, which would lay the foundation for theoptimized design of the generator.Firstly, the iron loss and ventilation channel eddy current loss of1000MWhydro-generator straight segment was calculated using the transient electromagneticfield in which the iron and ventilation channel was cut into several sub domains. Theiron loss and ventilation channel loss of every sub domain were obtained, whichwere considered as heat source. The fluid flow velocity in stator radial ventilationgroove and stator temperature distribution were obtained by fluid-thermal coupledfield.Secondly, the structure of ventilation channel was optimized in this paper. Theinfluence of stator ventilation channel bending angle, bending form, radial positionand circumferential distance on fluid flow and stator temperature was analyzed.Cutting a certain distance of ventilation channel in the junction of the stator toothand yoke was proposed, and the influence of stator ventilation channel cutting lengthon ventilation channel eddy current loss, fluid flow and stator temperature wasanalyzed.Finally, the electromagnetic field of stator end was calculated bythree-dimensional harmonic field. The magnetic field distribution of stator endregion and the eddy current loss of stator end structure were obtained. The meshingresults of electromagnetic field were loaded into the temperature field, and the lossof every element in electromagnetic field was considered as heat source intemperature field, which coupled the electromagnetic and temperature field. The three-dimensional steady-state temperature field of the stator end was solved by thefinite element method, and temperature distribution of stator end structure wasobtained.