Heat transfer enhancement from power transformer immersed in oil by earth air heat exchanger

Abstract

In this study, the modelling of power transformer with (250kVA) by using (ANSYS17.1/FLUENT) code program was done. The power transformer was connected with earth air heat exchanger to decrease the temperature of (oil, core, and coils) of transformer which will increase its efficiency for preventing the damage and/or failure. The case study used the weather conditions of Nasiriya city (Iraq) at 1July with 50°C as maximum ambient temperature and full electrical load of the power transformer. In addition to different pipe diameter, length of earth air heat exchanger and different air velocity entering to pipe. The results showed the temperature of (oil, core, and coils) for power transformer decreased with increase the pipe length and earth air heat exchanger depth underground. The air velocities inlet to earth air heat exchanger that used in the study were (2, 4, 6 m/s respectively)and the results showed the increasing of air velocity inlet to earth air heat exchanger should decrease the temperature of (oil, core, and coils) for power transformer and increase the thermal conductivity of oil. The study concluded when using earth air heat exchanger in the power transformer and performance of power transformer will be increasing and led to decrease the temperature of oil about (18.5°C).The results showed a significant convergence with previous researches.