Numerical Analysis Of Coupled Field In Large Air-cooled Turbo-generator Under Different Load Cases

In recent years, with the invention of new materials, the installed capacity ofgenerators is increasing constantly, more and more engineering prefer to selectingair-cooled turbine generator. However, the increment of unit capacity added thecomplexity of turbo-generator and the force of electromagnetic load，the heatingproblem of turbo-generator increasingly serious. Therefore, accurate calculation ofair-cooling steam turbo-generator having engineering sense.For above issues, a150MW air-cooling turbo-generator is taken as example inthe paper,2D model of turbo-generator is built, and the iron loss is calculated usingfinite element method and distribution characteristic of iron loss is analyzed. Themathematical representations of eddy current were presented from detailed derivationin this paper. And the resistance enhancement coefficients and the value of eddy lossof stator windings were determined, the distribution characteristic of eddy current ofstator windings in turbo-generator was analyzed.Starting from the basic theory of electromagnetic field and temperature field,Meanwhile combining structural characteristics of generator, and3D models of150MW air-cooled turbo generator establishes a pressing ring, magnetic shielding,plate, pressure point, stator and rotor core end (including core ventilation ditch), rotorend windings and other components were build in this paper. The related boundaryconditions and basic hypothesis were also discussed.Finally, based on the calculation of the thermal fields in end-stator region ofair-cooling steam turbo-generators, which through delicate the3D model and statethermal field, the temperature distribution was gained, and the distribution laws wereanalyzed.