Heat Transfer Simulation and Experimental Verification of the High-Voltage Air-Insulated Bus Ducts

High-voltage air-insulated bus systems are often used in power generation and in receiving and transforming facilities as the electric feeder lines. They consist of aluminum or copper conductors encapsulated in aluminum casing. Joule heat losses are generated due to extreme values of AC currents (up to tens of kA) flowing in the conductors and induced in the casing. Air natural circulation and radiation in the closed area of the casing and in the open space of surroundings allow heat to escape to the environment. A 2D sequential coupled field magneto-thermal finite element model was developed. The solution of the heat generation rate due to applied and eddy currents as well as skin and proximity effect is obtained using ANSYS/Emag. The solution for the fluid flow and the temperature distribution is obtained using ANSYS/FLOTRAN via an iterative process. The results of the electromagnetic analysis are the inputs to the CFD analysis and vice versa until the equilibrium state is achieved. Temperature-dependent material properties for both types of analyses are considered during the solution process. The analyses were performed for different types, dimensions and loading conditions of the bus ducts. Good agreement between the analytical model and experiments was achieved.

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