Heat analysis of the power transformer bushings using the finite element method

Reliability of power transformers significantly depends on the performance of their bushings and bushing lifetime is mainly dependent on its hottest spot temperature, which is caused by the power dissipation in the bushing's conductor. In this paper, the thermal analysis of the bushing is firstly performed in two-dimensional space using the differential equations. Then, the Finite Element Method (FEM) is employed to determine a bushing's temperature distribution and specify its hottest spot. The effects of increasing the temperature on the bushing's conductor are also investigated and the results are compared in different currents. The proposed method calculates the temperature distribution in all parts of bushing including conductor surface, paper, porcelain and oil. It is useful for manufacturer and utilities to evaluate the insulation design, temperature distribution and loss of insulation life.