Positioning Tank-Wall Magnetic Shunts of a Three-Phase Power Transformer Considering Thermal Effects

This article presents an investigation of the optimal positioning of tank-wall magnetic shunts in power transformers. Magnetic shunts are made of grain-oriented magnetic silicon steel laminations and are used to avoid hot spots in metallic regions inside the power transformer. The magnetodynamic equations are solved in terms of the electric vector potential and the magnetic scalar potential. Thermal effects are calculated using heat transfer coefficients. This article proposes and solves an optimization problem where the objective is to position several shunts near the tank wall. Several design variables, temperature, and geometrical constraints are considered. As the finite-element (FE) model to be solved is in 3-D, the computing resources must be efficiently used. A multi-threading method was developed and numerically tested where the 3-D FE model, temperature calculation, and the particle swarm optimizer (PSO) are executed in a multicore computer in a parallel scheme.