To accurately understand the temperature distribution inside the cast-resin dry-type transformer for assessment of transformer insulation life

the temperature field in the dry-type transformer is calculated on the basis of heat transfer theory and fluid mechanics. First

a coupled thermal-hydraulic analytic model is built

and a physical model of the cast-resin dry-type transformer is established with the software COMSOL to calculate the temperature distribution of its components such as ferrite core and windings. Comparison between the simulation result and the measured one indicates that the physical model is accurate with an error of less than ±5.5%.According to the simulation

the temperature distribution of windings and core shows a low-high-low trend from the bottom up

and the hottest spot is located in low-voltage winding at 85% height from bottom. The correlation between winding temperature distribution and loading rate is limited

and hot spot maintains a relatively fixed position.