As the main power supply line, dense bus ducts are prone to safety hazards in humid environments due to decreased insulation performance. Protection requires a comprehensive approach encompassing structural design, sealing, environmental control, material selection, installation standards, monitoring and maintenance, and emergency response.
Structurally, while the compact arrangement of dense bus ducts increases current-carrying capacity, it also restricts airflow, resulting in weaker heat dissipation and moisture protection. To address this, optimizing conductor spacing and housing structure can increase heat dissipation channels while maintaining compactness, such as using a housing design with ventilation holes. However, a balance must be struck between ventilation effectiveness and protection level to prevent direct moisture intrusion. Furthermore, adding insulating supports inside the dense bus duct enhances structural stability and reduces poor conductor contact caused by vibration or thermal expansion and contraction, indirectly improving insulation reliability.
Sealing is the core element in preventing moisture intrusion. Connections, inlets, and wall penetrations of dense bus ducts are vulnerable points for moisture penetration. Therefore, high-temperature resistant and aging-resistant sealing materials, such as silicone sealant or EPDM rubber sealing strips, are required for double sealing of flange gaps and manholes. Gaps between wall sleeves and walls should be sealed with fire-retardant putty or sealant to prevent rainwater or moisture from seeping in. Regularly inspect the seals for aging and replace cracked or deformed sealing strips promptly to ensure continued effective sealing.
Regarding environmental control, if dense bus ducts are used in humid environments, external equipment is needed to regulate the local microclimate. For example, adding dehumidification devices, such as external drainage dehumidifiers or industrial dehumidifiers, within the installation space can maintain air humidity within a reasonable range. For enclosed dense bus ducts, hot air drying can be used, introducing heated, dry air through a dedicated interface to accelerate moisture evaporation; alternatively, vacuum drying can be employed, where severely damp dense bus ducts are evacuated and then injected with dry nitrogen to circulate and replace the moisture. Furthermore, maintaining a clean installation environment and reducing dust and dirt accumulation can lower the risk of surface discharge due to moisture adsorption.
Regarding material selection, the moisture resistance of the insulation components directly affects the long-term reliability of the dense bus duct. Insulation materials with low hygroscopicity and high dielectric strength, such as epoxy resin, polyester film, or silicone rubber, should be selected, avoiding the use of easily absorbing paper or cotton insulation. Simultaneously, conductor connections require anti-oxidation treatment, such as applying conductive paste or tin plating, to prevent increased contact resistance and localized overheating caused by moisture oxidation. For the casing material, highly corrosion-resistant stainless steel or aluminum alloys are preferred to reduce seal failure due to casing corrosion.
Installation specifications must be strictly followed, adhering to construction standards to prevent moisture intrusion caused by improper installation. For example, when a dense bus duct passes through multiple floors, a waterproof dike or baffle should be installed to prevent water from leaking down the duct. During installation, the dense bus duct should be kept level to avoid internal water accumulation due to tilting. The tightening torque of connecting bolts must meet requirements to prevent seal failure due to loosening. Furthermore, sufficient operating and maintenance space should be reserved around the dense bus duct to avoid poor ventilation or maintenance difficulties caused by limited space.
Monitoring and maintenance are crucial for preventing insulation degradation. The insulation resistance of the dense bus duct should be tested regularly, using a megohmmeter to measure the phase-to-phase and phase-to-ground insulation resistance values and comparing them with the initial values to determine if insulation performance has declined. Simultaneously, check the surface of the dense bus duct for condensation, water film, or discharge marks, and check conductor connections for oxidation due to moisture; clean and tighten as necessary. For dense bus ducts operating in harsh environments, temperature and humidity sensors can be added to monitor internal environmental parameters in real time, automatically activating a dehumidifier when humidity exceeds the standard.
If a dense bus duct has become damp, resulting in reduced insulation, it must be shut down immediately and emergency measures taken. For lightly damp dense bus ducts, hot air drying can be used, blowing hot air into the interior to accelerate moisture evaporation. For severely damp dense bus ducts or those that have experienced discharge, they must be disassembled and the insulation components re-dried. The conductors and insulation components must be inspected for damage, and damaged components replaced if necessary. After treatment, the insulation resistance must be tested again to ensure it meets safety standards before the bus can be put back into operation.
