AC-voltage performance of field aged glass insulator strings

This paper presents the AC-voltage withstand performance of field aged 110kV transmission line glass insulator strings investigated under different environmental conditions. Insulator strings were removed from two 110 kV lines, one located near a coastal area and steel mill industry and the other located inland next to a dump. AC-voltage withstand levels were tested and leakage currents across insulator strings were measured in dry, mist and wet conditions. Results suggest that the polluted insulators from the steel mill should be replaced whereas protective measures need to be applied to the insulators at the dump to mitigate bird-related problems.