Layout Optimization of Hybrid Ventilation Inside the Main Transformer Room for a Typical 110 kV Substation in Zhengzhou City

This work focuses on a typical 110 kV indoor substation transformer room in the Yellow River Basin. Safety alarms frequently occur during the summer, significantly impacting the safe operation of equipment. The Computational Fluid Dynamics (CFD) results revealed an apparent airflow short-circuits and uneven flow distribution in the existing system, leading to localized high temperatures near the transformer. To address this issue, a hybrid ventilation of involving both natural and mechanical ventilation was proposed. Firstly, considering the principles of thermal pressure, the actual placement, as well as the heat dissipation characteristics of the main transformer, the natural ventilation system was reconfigured. Five ventilation layouts of outlet were proposed. The research results indicated even arrangement of outlets into six showed the highest heat-dissipating capacity, with a minimum average temperature of 39.60 ℃ on the same vertical Z-axis horizontal section, significantly lower than the original system of 43.39 ℃. This layout increased the natural ventilation flow from 10,886 m³/h to 12,700 m³/h by enhancing thermal pressure, resulting in a more uniform distribution of airflow. Based on the optimized natural ventilation layout, two different mechanical ventilation modes were investigated: mechanical exhaust and mechanical supply. The former mode displayed a lower exhaust temperature of 39.6 ℃ than the latter of 41.6 ℃. This work provides a reference for the efficient heat dissipation and safe operation of main transformer rooms in the relevant area.