Hydrophobicity Retention, Recovery & Transfer: Usage & Test Standards
by Stefan Kornhuber

Functionality and service life of composite insulators depends largely on surface and/or interface ageing of the polymeric housing. Hydrophobicity and sealing of the rod by the silicone material must be guaranteed over the insulator’s entire life cycle since, if lost, leakage currents can flow through the moistened pollution layer. Understanding hydrophobicity behaviour as well as the processes that can lead to its reduction and recovery is therefore crucial to select the right material for an insulator. Hydrophobicity transfer is already included in IEC TR 62039 and results of multi-stress testing to investigate its retention and recovery have been summarized within CIGRE. This presentation will provide an overview of these test methods and results.