Numerical Study on Electromagnetic Coupled Heat Transfer and Ultrasonic Propagation in GIS Busbar Chamber

In the present paper, the electromagnetic coupled heat transfer and ultrasonic propagation in a 252 kV three-phase GIS busbar chamber were numerically studied by using the finite element method. The electromagnetic loss and distributions of SF6 gas velocity, temperature, and breakdown margin in the GIS busbar chamber were carefully analyzed, and the influences of SF6 gas velocity and temperature variations on ultrasonic propagation performances in the GIS chamber were discussed in detail. It is found that the SF6 gas breakdown margin in the GIS busbar chamber is mainly affected by the electric field intensity. When I = 3300 A and U = 1050 kV, the minimum SF6 gas breakdown margin in the GIS busbar chamber is 7.98 kV/mm, which is located at top of busbar conductor A, where the thermal breakdown risk is relatively high. Furthermore, it is noted that, when natural convection in GIS busbar chamber is weak, the influences of SF6 gas velocity and temperature variations on sound propagation would be insignificant. For this case, when acoustic propagation simulation is performed, the SF6 gas would be assumed to be stationary and its temperature would be set to the average gas temperature of natural convection in the GIS chamber, which would be beneficial to reduce the computational time and maintain the simulation accuracy as well.