LAUSR

ABSTRACT Losses in a three-phase transformer can be minimised to a considerable extent by improving the core design. In this paper, a new proposed model (hexagon and hemisphere) of T-joint designs is presented as one of the solutions to reduce the losses for a three-phase transformer. The behaviours of magnetic flux density, load variation, core and winding temperature have been considered and discussed accordingly in this study. The losses of the core and windings were considered a heat source inside the transformer. A nonlinear behaviour of the core material and a 3D finite-element method were employed for the simulation of the proposed models of the transformer cores. The simulation results of the proposed models showed a reduction of no-load and total losses ranging from 7% to 16% compared with the conventional designs. The verification of the results was compared with the experimental results for the 1 MVA and the 11/0.433 kV distribution transformer. This work confirms that it is still possible to reduce the losses of transformer by reassembling the core, particularly in the joint area.