Performance of 115 kV Fiberglass Transmission Crossarms in Wet and Salt Fog Environments

This paper discusses 60 Hz-dielectric tests performed on 115 kV solid fiberglass transmission crossarm-insulator asserblies to evaluate their performance in wet and salt fog envirorents. Testing included the following variables: (1) wet and dry conditions, (2) new and used crossarms and insulators, (3) type and number of insulators, and (4) salt fog salinity. Analysis of test results shows that the surface coating of fiberglass insulation is susceptible to degradation in a salt fog enviroment. Once this coating is eroded and the glass fibers are exposed, carbonized tracking develops. The fiberglass crossarm thus loses its electrical strength.