Oil-immersed transformers are critical equipment in power systems for transmitting and distributing electrical energy

and their normal operation is essential for the stability and reliability of the power system. To improve the computational efficiency of fluid-thermal simulation for oil-immersed transformers

this paper proposes a parallel computing method for fluid-thermal fields based on domain decomposition. First

the Schwarz overlapping domain decomposition method combined with the finite element method is employed for computation. Instead of traditional domain decomposition software like METIS

the centroid coordinates of finite element mesh cells are used to decompose the domain

ensuring more uniform subdomain sizes and better control over the overlapping area. Computational efficiency is further enhanced by optimizing the number of subdomains and the size of the overlapping regions. Second

the parallel pool function in MATLAB is utilized to implement MPI-based parallel computing. Finally

a steady-state fluid-thermal calculation model for an oil-immersed transformer is established to validate the effectiveness of the proposed method. The fluid field is solved by using the least-squares finite element method with a two-sided balancing preconditioner

while the temperature field is solved by using the upwind finite element method. The results show that the computation time is reduced by 40.3% for the fluid field and by 56.4% for the temperature field

effectively improving the simulation speed for transformer fluid-thermal analysis.