A novel dissipating heat structure of converter transformer RIP bushings based on 3-D electromagnetic-fluid-thermal analysis

With the increase of transmission power in China, the heating problem of converter transformer resin impregnated paper (RIP) bushings is increasingly serious. In this paper, applying the computational fluid dynamics (CFD), using a 3D electromagnetic-fluid-thermal analysis method, and considering the heat conduction, convection, and radiation effects, the temperature field distribution of the converter transformer RIP bushing has been simulated; according to the simulation results, the maximum temperature of epoxy impregnated paper is above the heat distortion temperature 120°C. Then, to verify the accuracy of the simulation method, temperature rising experiment has been carried out. Through the comparison, the temperature difference percentage between the simulation results and the experimental results is within 9 % proving the rationality of the simulation method. Finally eight optimization schemes for the 400 kV converter transformer RIP bushing were proposed which include the heat conductors with different diameters and numbers and the thermal conductive oil inside the inner conductor. Through the simulation of the eight optimization schemes, it can be proven that the heat conductors and the thermal conductive oil inside the inner conductor can effectively decrease the temperature distribution of converter transformer RIP bushings and improve the stable operation of transmission line.