Modified IEC 5000-h Multistress Aging of 28-kV Thermoplastic Elastomeric Insulators

The 28-kV, novel, environmental-friendly, thermoplastic elastomeric insulators were tested under slightly modified IEC 1109 5000-h (Annex C) conditions for their long-term performance. The modifications were made to more closely represent the actual service environment than the conditions used in the IEC. Various stresses applied include UV-A radiation, heat, rain, clear mist and salt fog, in addition to electrical. After 5000-h aging, there was discoloration, loss of hydrophobicity, and a loss of hydrocarbon bonds. Overall, the insulators looked intact despite the molecular and microstructural changes