Analysis on the magnetic shunt structure of large power transformer

Installing magnetic shunts on the surfaces of tank and clamps of power transformer is able to reduce the eddy current losses and decrease the temperature rise effectively. Here, the three-dimensional transient finite element method and the magnetic thermal coupling method are used to calculate and analyse the effect of magnetic shunts with different structures. The non-linear magnetic property of both the transformer structural parts and the magnetic shunts are considered in the analysis. The lamination structure of the shunt is also considered, which is simulated by a thick plate with anisotropic magnetic property. A 334MVA single-phase transformer is taken as an example in the analysis. The optimisation shunt structure is obtained. By comparing the L-shaped, the inverted L-shaped, and the U-shaped magnetic shunts for the clamps, it is proved that the U-shaped shunt is more effective in reducing the eddy current loss and temperature rise.