Numerical simulation for optimising of inlet and outlet positions for mechanical ventilation and heat dissipation: A case study to improve ventilation in an indoor 110kV substation

Efficient ventilation and heat dissipation in indoor substations are crucial for the stable operation of transformers. This study investigates the impact of inlet and outlet positions on ventilation and heat dissipation performance in a 110 kV indoor substation using CFD. A model of the 110 kV main transformer chamber is developed. Twelve combinations of inlet and outlet positions are analysed. Inlet positions include side walls parallel to radiators, side walls perpendicular to radiators and both side walls perpendicular to radiators. Outlet positions include the top of the chamber, the side of the inlet, adjacent to the inlet, and opposite inlet. Results demonstrate that locating outlets at the top of the chamber reduces transformer temperature by 0.5–1.6 ℃ and increases energy utilization by 8.6%–24.8% regardless of inlet position. Two opposite inlets perpendicular to radiators allows even air distribution between radiators. This configuration reduces transformer temperature by 3.4 °C when the outlet is located at the top of the chamber. Overall, the optimal ventilation design involves top chamber outlets and inlets on opposite walls perpendicular to radiators.