Image analysis of dynamic drop test to measure the retention of hydrophobicity of polymeric insulating materials

摘要

Since silicone rubber has good hydrophobicity, lightweight and stain-resistant, it is used for polymeric outdoor insulators. However, we have not evaluated the retention of hydrophobicity under AC and DC voltage stress yet. Therefore, CIGRE starts Dynamic Drop Test (DDT) which is still under specification for Round Robin Tests. In this paper, we can evaluate time variations of hydrophobicity by applying image analysis during the DDT. Image analysis is able to measure the change of maximum water droplet length from top electrode and the maximum water droplet length follows the retention state of the hydrophobicity of polymeric insulating materials.