An examination of the service performance of ceramic insulators

High quality porcelain has proved itself as an outstanding, reliable and permanent insulator material. Detrimental processes like tracking, erosion and weathering, which severely limit other materials, are totally resisted by porcelain which, when used as a housing is also impenetrable to water vapour. The evolution of tensile loaded disc insulators over nearly a century has resulted in negligible failure rates for properly made units. Furthermore the sources of failure are more often in the metal fittings or the cement rather than the ceramic itself. The author discusses insulator design, mechanical loads, electrical stress, and service performance of cap and pin insulators