Abstract：In response to the partial discharge and metal component corrosion issues in the busbar bridge of a 10 kV distribution equipment room at a 220 kV substation in Quanzhou, Fujian, this study reveals the fundamental mechanism of condensation formation through field testing and theoretical analysis. Research indicates that inadequate building sealing coupled with deficient ventilation control creates thermal stack effect-driven airflow between vertically adjacent spaces, causing moisture-laden hot air to continuously contact and condense on cooler equipment surfaces. The heat and mass transfer process is analyzed based on humid air thermodynamics, and the inevitability of condensation is quantitatively verified through dew point calculation. An integrated solution is proposed, featuring “airtight sealing as the foundation, coordinated temperature-humidity control as the core, and intelligent monitoring as the safeguard”. Precise management of the environmental dew point is achieved through building airtightness improvements and coordinated operation of air conditioning and dehumidifiers. Engineering applications demonstrate that this approach effectively eliminates condensation and discharge risks, maintaining post-treatment room relative humidity stably within (50±5)%, providing a reliable solution for moisture prevention in substation design and operation within hot-humid regions.
2026, Vol. 27 
