Study on the hotspot distribution characteristics of oil immersed transformer based on electromagnetic-fluid-thermal fields coupling analysis

Power transformer is one of the key equipment in power system. The main failure factor of oil immersed transformers is the high temperature generated during operation. Therefore, it is necessary to study the hotspot distribution of iron core and winding temperature of oil immersed transformers. This paper analyzes the tendency of winding, iron core and oil in the course of temperature rise and cooling stage. And the distribution area of hotspot temperature is clear eventually. Three-dimension model of oil immersed transformer is established by the finite element software. And the distribution of temperature can be obtained through the accurate calculation and analysis on the coupling field of electromagnetic-fluid-thermal. The conclusion of electromagnetic analysis is generated into the thermal field model as the pre-additive load in the thermal analysis. The conclusion of thermal characters studied before is verified. And a deeper comprehension of hotspot temperature is obtained simultaneously.