Resultant magnetic fields due to both windings and heavy current leads in large power transformers

The eddy current field due to both windings and heavy current leads (HCL) in large power transformers is analyzed by using the improved T-/spl Omega/ method, in which T and /spl Omega/ can be solved separately in different subregions. Thus, storage capacity and CPU time can be saved to a great extent. In addition, the local overheating on the tank wall near the magnetic shield gap is calculated and analyzed, and improvement measures are proposed. On the basis of this work, a composite shield is analyzed and optimized. The numerical results show that the eddy current losses are reduced and the local overheating is removed by using this composite shield.