Electrical–thermal effect of localized arcs on the surface of contaminated insulating materials under condensation

In high humidity and salt spray environments, the surfaces of insulating materials are prone to condensation, which causes surface discharge accidents and reduces insulation performance. First, focusing on the electrothermal effect of the localized arc on the surfaces of insulating materials in condensation conditions, the condensation growth characteristics under different environmental factors are studied. Second, the electrothermal characteristics of the localized arc are evaluated based on the characteristics of condensation distribution. Finally, multi-physics coupling simulations are carried out for comparison. The results show that the numerical simulation and experimental results follow the same trend and are highly consistent. The maximum relative error between the two temperatures is 9.34% when the sewage concentration is 5 mg/ml. The discharge under condensation is due to the combination of multiple physical parameters such as electricity, heat, and light. The arcing voltage is negatively correlated with air velocity, temperature difference, and relative humidity but positively correlated with ambient temperature. In addition, non-environmental factors such as electrode shape and wetting degree have a significant influence on the arc starting voltage. The electrothermal effect of the localized arc further leads to a significant decrease in the hydrophobicity of the insulation materials.