Layer-Type Power Transformer Thermal Analysis Considering Effective Parameters On The Temperature Rise

Since large power transformers belong to the most valuable assets in electrical power networks it is suitable to pay higher attention to these operating resources. Thermal impact leads not only to long-term oil/paper-insulation degradation; it is also a limiting factor for the transformer operation. Therefore, the knowledge of the temperature, especially the hottest spot (HST) temperature, is of high interest. This paper presents steady state temperature distribution of a power transformerlayer-type winding using conjugated heat transfer analysis, therefore energy and Navier-Stokes equations are solved using finite difference method. Meanwhile, the effects of load conditions and t ype of oil on HST are investigated using the model. Oil in the transformer is assumed nearly incompressible and oil parameters such as thermal conductivity, special heat, viscosity, and density vary with temperature.Comparing the results with those obtain ed from finite integral transformchecks the validity and accuracy of the proposed method.