The Study Of The Eddy Losses And Temperature Field Of Windings In Power Transformer

At present, the low loss and overheating control for power transformer is a very important and difficult problem which need resolve, and it is significant to ensure long-term safe operation of the power system. On account of the capability of unit transformer increasing with the enlargement of power system capability, research on stray losses and practical overheating caused by leakage magnetic field is very useful.The powerful finite element software—OPERA (Operating Environment for Electromagnetic Research and Analysis) is introduced and used in this paper. Adopts electromagnetic theory, a 2-D leakage magnetic field model of a power transformer is built with a lot of simulation analysis for a 2-D model of transformer. The eddy current loss of the winding is calculated accurately on the basis of the analysis of 2-D leakage magnetic field of the transformer. The distribution of magnetic flux density along radial and axial direction is compared of high voltage winding and low voltage winding, and the eddy current loss is analyzed combining with the distribution of the magnetic flux density of high voltage winding and low voltage winding.Coupling with the temperature field on the basis of the total loss of the windings, acquired the diagram of winding's temperature rise, analyzed the result with heat transfer theory, and gave a scheme to improve the disc-coil's distributing of directed district in forced-directed oil cooling transformer. The scheme proved in theory is feasible, and it provides the theoretical basis for the design of power transformer.