In humid environments, anti-condensation measures for box-type substations require systematic optimization across four areas: sealing, environmental control, material optimization, and operation and maintenance management. This approach minimizes the impact of condensation on equipment insulation performance and operational safety.
Sealing is fundamental to preventing external moisture from intruding into the cabinet. The cabinet bottom, cable holes, and joint gaps in box-type substations are primary pathways for moisture intrusion. If the bottom is not properly sealed, accumulated water in the cable trench can flow directly into the cabinet through the flue effect. Microscopic gaps between cable holes can also serve as pathways for moisture penetration. To address these issues, high-viscosity, high-density BBS anti-condensation hermetic sealing material is required. This material penetrates the tiny gaps between cables, forming a dense barrier to minimize moisture intrusion. Furthermore, waterproofing should be applied to the connection between the box and the cable trench, such as by applying waterproof paint or installing waterproof baffles, to prevent rainwater from backflowing.
Environmental control requires reducing cabinet humidity through ventilation, heating, and dehumidification technologies. Natural ventilation is a fundamental measure. By installing appropriate vents in the cabinet, air convection is used to reduce the temperature difference between inside and outside the cabinet and the relative humidity. For confined spaces, we can draw on experience gained in switchgear management by adding vents on elevated floors to counteract the flue effect and reduce moisture accumulation. Heater retrofits utilize a "low-power constant operation + high-power humidity control" model. Temperature sensors monitor the cabinet's humidity in real time. When the humidity exceeds a threshold, the high-power heater automatically activates to rapidly reduce the relative humidity. Furthermore, installing cabinet air conditioners or heat exchangers can achieve precise temperature control and dehumidification. Air conditioners enhance air convection through a cooling cycle, controlling the cabinet's temperature and humidity. Heat exchangers utilize high-thermal conductivity components to filter and exchange air between inside and outside, maintaining a manageable temperature difference. When humidity is high, heated air ventilation is activated to further reduce humidity.
Material optimization can enhance the cabinet's inherent moisture resistance. Given the long-term exposure of outdoor box-type substations to humid environments, upgrades to sealing strips, hanging rings, and the cabinet structure are necessary. Traditional sealing strips are prone to failure due to aging and UV exposure. However, EPDM airbag sealing strips offer high and low temperature resistance, UV resistance, and a long lifespan, effectively preventing rainwater infiltration. The top rings of the control cabinets require waterproofing with a special bowl-shaped waterproof seal and sealant to prevent leaks caused by loosening and rust. Furthermore, single-layer smart control cabinets can reduce heat conduction and prevent condensation on the cabinet walls by applying thermal insulation coatings to the cabinet exterior, adding flame-retardant insulation to the top and sides, and replacing the viewing window material (such as replacing glass with PC).
Operation and maintenance management should establish a regular inspection and emergency response mechanism. Operators should regularly open cabinet doors for ventilation and check the operating status of components such as heaters and dehumidifiers to ensure they are in proper working order. Cabinet sealing should also be inspected, focusing on issues such as aging sealing strips and cracking in joints, and damaged components should be replaced promptly. During seasons with high condensation rates, inspections can be increased, and tools such as infrared thermometers and humidity sensors can be used to monitor cabinet environmental parameters to identify potential hazards in advance. In addition, an emergency plan needs to be formulated. When the humidity in the cabinet exceeds the standard or condensation occurs, the dehumidification equipment should be started immediately, ventilation should be increased, and the intrusion path of external water sources should be checked to prevent the problem from expanding.
