Analysis Of The Impact Of High Humidity Water Film Formation On Creepage Discharge In Cable Terminals

In high humidity environments, a thin water film can easily form on the surface of terminal lugs. Air itself is a good insulator, but when moisture is adsorbed on the surface of copper lugs and the insulator, the presence of this water film will reduce the barrier performance between the materials and provide a path for surface leakage current. Similar to the situation where moisture on the PCB surface causes an increase in leakage current, this type of conductive film can significantly reduce the insulating surface resistance of Aluminum Cable Lug, allowing the small current under the influence of the electric field to flow along the surface without being isolated by the air.

Once the conductive water film forms, a conductive path appears between the two charged components at component Compression Cable Lug. Under the influence of the electric field, the leakage current along these paths generates micro-discharge phenomena in localized areas, gradually increasing the local temperature and accelerating the degradation of the insulation material. This discharge process forms carbonization marks on the insulation surface, leading to the formation of even lower impedance conductive paths and further exacerbating the discharge behavior. In electrical engineering and high-voltage systems, this phenomenon is called surface tracking, a typical mode of insulation failure.