Eddy current fields and overheating problems due to heavy current carrying conductors

Large complex problems, eddy current fields and local overheating due to heavy current carrying conductors (HCCC) including leads and connecting bus bars in a 360 MVA/500 kV power transformer, are analyzed by the boundary element method. To improve numerical accuracy, this paper chooses triangle polar coordinate mapping and addition-substraction techniques to evaluate singular integrals. The distributions of magnetic flux and eddy current densities in metallic parts of different materials are discussed. According to the criterion of overheating, permissible lead current and limiting distance between HCCC and metallic parts and arrangements of HCCC are suggested