| Large po wer transformer occupies a p ivotal pos itio n in the po wer system. Stray loss multip lies with the increas ing capac ity of a single transformer, whic h results in reduced operating effic iency and accelerated aging o f the transformer. Trad itional shield ing measures no t only lead to ineffective shield ing but also bring new ho t spots; it has been unab le to meet the requirements of large-capac ity power transformer. Therefore, it’s very necessary to find a new way and shield its correctness by simulation.This paper s imulates the running transfo rmer of typ e SSZ11-1800000/220, and us es ANSYS finite element s imulation software for its comp lex mod els which are reasonab ly s imp lified, the main wo rk is as follow:1、Three-d imens ional s imulatio n model is estab lished accord ing to the actual s ize of the transformer. By lo ad ing the appropriate boundary conditions and exc itatio n source, magnetic flux leakage and eddy c urrent losses of wind ings and eac h structural memb er are s imulated; the results are then compared with the theo retical values to verify the correctness of the simulatio n analysis.2、On the bas is of the s imulatio n analys is, the shield is adopted to red uce the eddy current loss. The shield performs good to reduce the edd y current loss of the c lip after s imulatio n. The vortex loss is reduc ed and the stress field o f the s lotted p late is s imulated and analyzed, the reasonab le slotting scheme fo r reduc ing the eddy current loss and the mechanic a l strength are obtained.3、The arc shield is adopted as a new method, which d iffers fro m the conventional rec tangular body to the o il tank with the largest magnetic flux leakage vo rtex. Then two kinds of simulatio n res ults are compared, the arc shield could really solve the p roblem res ulting fro m that general shield ing edge vortex dens ity is too concentrated to produce a new hot because o f the magnetic flux leakage of winding circumferential spot. |
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